Well I think many people forget that the true level of our characters doesn't stop at 60. Its not even much of a factor.
Our REAL levels, truly, are our ilvls. There are various instances where gear makes a somewhat big difference in 50 dungeons, between 50-60 dungeons, and yes even in 60 dungeons. Granted there is some room for skill to make that factor, but also a fair portion is the gear itself. I don't expect a fresh 60 with (what is it 180?) gear that just hit the requirement to preform the same feats as someone in 240 gear.

Granted there are examples that don't have to do with what I just mentioned...but please if you as a player haven't already, before getting upset at say, a tank not being able to pull an insane number of monsters...check the tanks gear...THEN check the healers gear. Heck even check the DPS gear because thats a fair factor as well.