I don't see the neccessity, especially in alliance raids it literally does not matter. But I wouldn't be against it as long as it's reasonable. Say, if the min iLvl is 600, you can't enter with gear under 560 or something like that. I can guarantee you that the vast majority of people with gear like this aren't trolling. They're new, leveling alt jobs, etc. Not everyone has the time to farm a bunch of dungeons to make sure they're geared up, or to spam roulettes/hunts/maps for tomes. Unless they're in content where it matters, it really isn't a problem.