Personally, I think it's balanced perfect at 90, as it makes the tanks usually 5-10 on my dps meters for 25 mans in raids. I don't really have an issue with it there.
I do really wish they'd put more effort into making it more balanced at low levels though. I know it's hard to balance low levels for everything, but here is where the effort should be made. It just doesn't feel right when I level a tank and look at recount and notice I'm doing 70% of the group's damage by myself, while also having sufficient heals to heal myself without a healer. Most tank classes can pretty much just solo any instance they come across without even outleveling it up until 65-70 if they really felt like it, and some even past that.