I think that all of this kinda depends on what loot system. Personnaly I believe:

Any pug you roll on everything, a 10 man.. well I only run with friends so no real problems, we go main specs first and armor based (cloth get dibs on cloth, leather for leather first ect).

I think DKP solves this issue, and you can let your characters build points just like normal members. Thats what my guild does for any of my alts, each one has their own set of DKP points so the more I play one the more gear they get. Course alot of times im the only shaman and am able to get geared pretty fast for one guy which I have done now, almost all 7.5 in two raids.

I think its a question of what you want, and whos in your raid. If you are doing most of the dps and beating out everyone then hell yeah roll x4, if your scrubbing along then you prolly shouldnt take gear from those that are really pulling their weight.