On the Jedi Covevant, 3 of our guild members were wanting to run some HMs. We had 2 DPS and one healer. We sat in que for 20 mins nothing happening. I log onto my tank, re-que, it instant pops. This is just one example of many. During prime time hours, healers should get decent ques... Outside of prime time, tank fare much better on my server.
Not only do tanks need special tank gear in addition to being the assumed leader, they required a greater understanding of both fights and mechanics. Unless you're an off-tank you can't just wing HM OP fights.
Even if you are an off-tank you can't wing HM OP fights. In many fights, tank swapping is needed so you have to have as much knowledge as the main tank.