Sydera at World of Matticus discusses Alts and the Raider: An Officer’s Perspective. We just went through some of this entering Naxx. It hadn’t been a big deal before Wrath as we had Karazhan on farm by the time we started to bring in alts to do more than fill in temporarily in key roles.
With Wrath, we’ve had an overfull raiding roster pretty much every raid night. Deciding who can come and who can’t has been a major headache for me and has led to hard feeling a couple of times. Some hadn’t decided on their spec and are willing to respec as needed which then leads to loot issues. Does a paladin without a declared spec get to roll on DPS/Tank/Heal loot? We ended up adding a new rule requiring raiders to declare a main toon and spec even if they are not playing that toon/spec at the moment. Farm content is going to be more of a free-for-all, but we’re a ways from having anything on farm at this point.
It’s naive of me, but I hadn’t even thought about this till someone brought it to my attention. Probably one of the reasons I hadn’t thought about it is that the loot didn’t affect me directly. I had blithely assumed the more alts, the merrier. With more alts we could have multiple people for any given role and we could pull in different toons to give everyone a chance to play. I missed considering the politics of loot distribution, especially in these early progression days when one piece of loot can make a big difference to someone’s raid viability.