Flexible raid group size

One problem with the raid dungeon in World of Warcraft is that they have a fixed number of slots, for example 40 for Molten Core. If you organize a MC raid, and only 30 people show up, you'll probably not get very far, unless the 30 are all MC-veterans in uber-gear. On the other hand, if 50 people show up, there will be 10 people unhappy that they can't go.

That is especially annoying on guild level, because it is pretty much impossible to have a guild size where exactly 40 people show up on every MC raid planned. There is always the risk of either there being a big football match on TV and less people than 40 attending, or there being more than 40 people starting to fight how to distribute the available raid slots. Things get even more problematic if your guild is too small to do MC alone, and you ally with one or more other guilds to go there. To guarantee that you get 40 people every time, you *need* to have more than 40 people interested, thus always disappointing somebody, and if its an alliance this causes tensions between the guilds.

That made me think back to City of Heroes / Villains, where dungeons are scaling the difficulty of the encounter with the number of people in the group. In WoW, the raid group size is "fixed" by the difficulty being fixed, and the obvious advantage of taking exactly as many people as maximum possible. But these dungeons are instances, and it would be perfectly possible to scale the difficulty of the encounters in Molten Core, and enable people to do MC with any group size between 20 and 40.

I mentioned before that my definition of casual was "not knowing today how much you will play tomorrow". The often heard sentiment that "casual players are excluded from WoW's high-end content" is pretty much based on that definition. Getting 40 people together on a raid is very difficult if all of these people have other commitments in life, and can't promise with certainty to have 4 hours available on a specific date. Making raid group sizes more flexible would help there.