There's just way too much pressure to class stack right now in 10 mans. Garalon is a case in point, but there's still too much pressure to bring ranged over melee, or bring a very specific class set up, both for buffs and for encounter mechanics, to the point where if I have even one class with two players in it, (like 2 paladins, or 2 hunters) things start getting problematic. This expectations for 10 man raids is starting to become really unreasonable.
Can a balanced (or even slightly imbalanced) team take down a fight like normal or heroic Garalon in 10 man? Yes, but that is irrelevant, because it is still SO MUCH EASIER if you have Rogues, Mages, and Warriors, instead of WW Monks, Warlocks, and Ret Paladins.
There's still a lot of fights where, yes, its technically possible to kill the boss with lots of melee, but it is still EASIER to kill it with ranged. It is just easier to raid with a heavy ranged comp than to bring melee. Please don't "solve" this like you did in Dragon Soul, with ridiculous buffs and really boring stand-still encounters, though.