Ramblings of a loon
Coop in video games
A good coop game needs to have mechanics or ways to make players want to play together.
A mediocre coop game have mechanics that forces players to play together, if they want to or not.
A bad coop game give you no reason to play together at all, just place you next to each others and does no more.
Trinity is a hard lock, you are forced to do this together in this form/shape.
A mediocre or even bad coop game can be played and be fun, if all the relevant players share the same mindset/motivation they can make it fun, despite the game.
The ideal would be mechanics that isn't forced, but multiply both(+) players, so players experience and learn/improve by gameplay, by seeing that combining aspects/skills yields better effects. This makes players want to be near each others to make use of it, while figuring out how to time their skills and improve their teamwork. (Example Combo's in GW2, if it had been developed further).
A good system makes players cover for each others weaknesses, this doesn't have to, and shouldn't, be full trinity.
Player+Player: When 1+1=2, two players will beat something twice as fast, if the game scales with double the amount of mobs, you spend the same time.
Player*Player: When 1+1=3, Two players will be greater than the sum of the parts. If the game scales with double the number of enemies, the players would still finish it faster.
Types
Just to have a way of categorising different scales of coop.
Type A - Empower coop. This is when the game is designed so players automatically find that they work better at whatever goals when they are together. When their mechanics interact with other players and empowers everyone. And also showing players that they can improve together to make better use of these.
Type B - Forced coop. This is when the game just tells you that you need X players and/or of Y type to play this. They can be designed around this and can be great experiences for what they are, but the actual coop design tend to be under-developed since they have the forced part compensate for that.
Type C - Ignored coop. Typically games that just adds a way to play two or more players together, but doesn't adjust or change the game/mode to do anything about it. Typically doesn't enforce players to even be anywhere near each others.
Why I think MMO coop is faulty by design
MMO's are supposed to be coop games, where players work together to overcome challenges, in the theme of old Fantasy books etc. That's the basic premise the entire games are built around, and yet I don't feel they do a good job out of it.
Empower
Some MMO's have enemies with variety of moves/attacks/AI that can make it difficult for solo or specific classes
Mechanics that interact with other players mechanics to create more effects, empower both.
Group content that scales well with the number of players
Forced
Most MMO's will force the coop in some way, usually through dungeons. And often things will be locked behind them in some manner (progression, loot, levels, story, skins, whatever)
Most MMO's uses a forced system like Trinity to lock you into place. This makes the coop feel forced rather than encouraged
Some MMO's have a higher difficulty for OW that it's hard to survive solo (forced coop)
Ignored
Open World/Story are often content where you play solo, or doesn't need other players, because it's trivially easy
Gameplay that creates large differences based on skill-level. (Guild Wars 2 is unfortunately guilty of this)
Efficiency (negative)
The focus tend to be shifted toward XP/gear/gold, and those becomes the main motivation to run the dungeons. And thus the primary focus becomes “Efficiency”, and most players are only focused on how to farm the dungeon rather than enjoying playing it. Gameplay focus more on grinding than adventure. (Player Problem)
Most MMO's have a level/gear system that will keep trivialise older content, including group content. And thus makes older content that was fun/interesting once into something you can rush through with character just for the loot. This depends a lot upon the game.
Content (negative)
Most MMO's have a level/gear system that will keep trivialise older content, including group content. And thus makes older content that was fun/interesting once into something you can rush through with character just for the loot. This depends a lot upon the game.
Thus most MMO's end up with a small window of time, where a dungeon will be viable/interesting, and you hope to get a random party through LFG/DF/etc that is on roughly the same level as yourself. Once that window is past (levelled past, geared past, know the dungeon reasonably well) it ceases to be interesting content.
Game Examples
Monster Hunter World
Empower:
Encounters scale and is possible from anything 1-4 players
Varied monsters/bosses, weapons can have good and bad match-ups, and ways to build around many of them.
All weapons have something to offer, even double of the same weapons
Player*Player: Learning to play together, you can learn new strategies, like stun monster with hammer to hit with maxed charged up greatsword to heads etc. Different weapons usually creates new strategies for other weapons to exploit.
Optional: possible to make support builds, like Wide-Range healer, but not required.
Forced:
Shared carts/deaths means players discouraged from trying to get carried out of their league
You can play all story missions coop, but have to wait until cutscenes finishes, not obvious.
Very build based game, more the later you progress through the game.
Ignored:
Skill difference is very obvious, and can make an encounter harder than soloing at times.
The usual, beginner player, getting a veteran in end-game gear, that murderhobos Rathalos 2 minutes.
MHW isn't the worst at this, but you can out-gear lower ranks.
Type A, everything is optional but is generally enhanced by playing coop, unless the skill level or gearing is very out of whack.
Guild Wars 1
GW1 forces X players for missions, but players can be replaced by henchmen, and later heroes.
Very build based game
With the addition of Heroes the game became full on team-build based, in which a single player can setup the entire team, and puzzle their way through an entire encounter/mission. Eventually ends up more practical to just setup the entire team for yourself, than to rely on other players.
Core gameplay unfortunately bores me personally.
Gameplay itself encourages a variety of builds to either synergize with the rest of the party or counter enemies
The coop aspect is to organise and match builds against the mission and execute
Type B, Type C with heroes since it's often easier and more reliable to just use heroes.
Guild Wars 2
The player-skill aspect of the combat means that once you pass a certain threshold of skill, you cease to need other players for most things, other than just more damage.
Thus most cooperative aspects of the game (Instances/OW-Meta) ends up as a pure DPS/rush fest.
Difficulty scaling (Metas) doesn't scale well, and never really threaten a medium skill player, and there is enough cleave/aoe damage on short cooldown that the solution always becomes more damage.
The few places that actually require some teamwork are the top/end content of the game (raids, t4 fractals, organised wvw). Which the game thus doesn't prepare/teach a new player for at all.
The Combo System is one of the best examples of a good Player*Player system, but has been completely neglected and ignored.
Player-Skill might be the biggest problem for the game as coop, as it's impossible to balance anything when players will vary so much in skill-level. One player can die to single risen in Orr on maxed out level 80, while another can solo dungeons.
Motivation for coop: trivialise content difficulty so you don't have to learn/improve, guarantee loot.
Honestly GW2 is a mix of all 3 types, depending on where and what you do in the game at the time.
Final Fantasy 14
Hard trinity means you need 1 tank, 1 healer, 2 dps for any dungeon (or 2x for 8man dungeons). The usual problems: You're dependent on others in specific configurations to play content, each role is hard locked with strengths/weaknesses that you can't overcome. You're usually dependent on a random matchmaking service (Duty Finder) to get dungeons done.
Path of the Damned: Is a rogue-lite dungeon that ignores trinity, and you can sign up with anything in any combination, and numbers. This is honestly a better coop experience than usual dungeons.
The game has a terrible split between the story/singleplayer that you can't do with others at all (and even have to split parties just to start them). And the Dungeons/Trials which are required by the story to progress which are forced 4/8 man group content with trinity.
Vast majority of OW is easy enough to solo with the Chocobo-healer that you don't need other players, though they're useful for more damage in FATE's.
Duty Finder is good/bad depending on what you get. It gives great bonus for the first time you run it per day, in order to appeal to veteran players so they'll run it, thus potentially help new players through the early dungeons and teach them. In practise most of the veterans just want to rush it as fast as possible for the bonus and get out and do something else. Essentially a “Player” problem.
Type B, can be Type C in Open-World/Fates
WarFrame
More players generally means more damage. It's possible to make support builds, healers, tanks, and many others. But in the majority of content you end up just nuking things down faster with more players.
Some missions are designed to split up players or force them to move around, in order to make players work together. But players have mostly found ways to dumb that down to simplistic patterns.
Options to “build” away most weakness, to be self sustained.
Overall difficulty isn't very high for the large amount of starter content a new player gets to interact with. Except for a few specific mission types (Fuck you radio towers!) you usually have little need for other players.
The main motivation for coop is: easier and more loot (Which offends me personally).
I can't make a proper judgement of this game, since I haven't gotten far enough into it to really judge all the later mechanics and modes. But the start where every new player has to go through is Type C, where the main motivation for other players is more damage and trivialise content.
Valheim
Empower:
Ignored:
Players put into same world, left do do their own thing, everything can be done separately.
The best use of coop is usually dividing tasks and gathering resources separately.
Most encounters are just as fast/easy solo.
Negative:
Type C, it's more a “come help me with this, I'm too lazy/bored to do it solo.” kind of experience.
Children of Morta
All characters can be played solo or duo/coop.
The map locks both players in, which is a forced mechanic.
Each character have strengths/weaknesses, that other characters can round out. Thus you'll almost always benefit from being near the other player, and act/react depending on what they do. But it doesn't force you into specific characters (trinity)
Player*Player
The Reset per map, changes up play styles constantly and forces players to adapt to new gameplay, instead of having a single perfected build.
Forced: Same map/screen
Despite the camera locking you in, I still feel the rest of the mechanics is strong enough to put the game into Type A. Some character combinations might not work very well though.
Trine
Has 3 different characters to choose from, that each play very different
Game is designed that there are usually multiple different ways to get past problems so each character has options
This leads to a coop experience that doesn't feel as restrictive as most others
There are several ways in which the characters can interact with each others, which makes coop feel more engaging
The main clash tends to be thief and mage, as they can often seem to ignore or hold each others back
Forced: Same map/screen
Type A, despite some minor forced elements.
Tyrian
Has a own dedicated two player mode, with own mechanics. Particularly that the two ships can merge into a single ship
Each ship has different weapons, thus does very different things, thus they support/fill each others out
When merged player 1 (dragonhead) gains control and player 2 (dragonwings) instead controls a turret
This leads to a gameplay where players have to work together but can also play separatedly, adjusting to the situation
This is a rare case of asynchronous coop gameplay
Personally really love this one
Forced: Same screen, due to game-type
Type A, despite some minor forced elements, but that is mostly because the game itself is built around those same forced elements, even in singleplayer.
Ikaruga
Has a 2 player coop mode, which is pretty much just 2 ships in the normal mode
Struggles greatly that different skill levels will just have one player die while the other plays longer until they die
Forced: Same map/screen due to game-type
Type C, really feels like they just slapped on the option and ignored it.
Board Games (Spirit Island + Sentinels)
Type A, pretty much the definition.