One of the things I haven't seen discussed much concerning the 10-man/25-man split in Cataclysm is how hybrid players are going to gear offspecs.
This is the situation I'm in, and I suspect it's one that a lot of other hybrid players would recognize; I play restoration in most guild 25-man and 10-man raids, but I tank just about everything else. On easier content, or on nights when we have too many healers show up, it's not unusual for a few people to haul out their DPS sets and go DPS for the evening.
As such, hybrid players (and particularly hybrids who have dual-specced into a role requiring a completely different set of gear) have an interest in keeping their offspec set up to date, and the best way to do this has typically been through 10-man raids where there's not much gear competition. I got 3 Sanctified feral pieces from heroic 10-man ICC, and I'm still using a few ToGC-10 pieces to tank as well. When you only have 10 players in a raid, the number of players angling for a given piece is necessarily small, and items go to offspec quickly.