Following the recent discussion on Tesh's blog about bringing the player vs bringing the class, I have an idea.
We've already seen games that are good at scaling the difficulty depending on how many players there are - for example, Diablo 2 and City of Heroes.
What if games customized the types of enemies that you were going to face, or their abilities, based on the combination of classes in your group?
For example, consider a simple trinity-style combat system with 8-person teams and 3 classes to choose from - tank, healer, damage dealer. Let's say a particular team consists of 4 tanks, 4 damage dealers, and 0 healers.
The game could adjust the enemies to keep the challenge level for the encounter at the desired level - there are plenty of tanks, so increase the rate at which DPS generates aggro. There are no healers, so reduce the amount of damage done by the mobs, and/or give the mobs less HP (so that they die faster, and hence don't slaughter the whole team).
This logic can be extended to other combinations of teams. There should be a law of diminishing returns though - for example in a 40 man raid, I would not expect the system to scale to make zero healers acceptable. But if there were only say, two healers, the system should be able to scale *to a large degree* to even out the challenge level of the encounter.
Obviously, it wouldn't be perfect. But, it would be tweaked based on data mining/player feedback, just the same as with current systems, and it would be a lot better than current systems where you if you don't have X amount of various classes, you just have no hope of beating the encounter. The benefit is that players would be much more free to bring whatever class they like, to experience the content that they're interested in. No more being pressured by your guild to level up a tank, even though you secretly hate playing them, etc.
Of course, I'm sure there'll still be the elitist top few % of players who want to compose the perfect team, and that's fine, that's half the fun of the game for them, so let them do it! But for the vast majority of average Joe's, this will let them just play your game to maximize their fun, without having to worry about whether they're going to get into an "end-game" raiding group with their selected build.
Thoughts or suggestions?