Hi there 
  
I've played Vanilla back in the day and sometimes in some private servers, still I never reached 60. The only experience I have raiding is in TBC as Warlock and I didn't find it that difficult, but I believe this is due I was playing the post nerf version. This time i'm fully committed to see all the end content. However Im afraid of my class choice, I want to pick a class that can let me progress without investing too much time (college). I mentioned Warrior in my question because I have a 55 Warrior in Old Nost and I enjoyed a lot tanking the dungeons available to my level, but I know tanking in higher levels involves much more knowledge, responsibility and some other things.  
  
I will be starting again in the fresh sever because I've never experimented such thing and I don't know if Warrior will help me to reach my goal. My other options are Priest and Shaman, I've never healed before, but I think this will be easier than tanking. Thanks for reading and your answer.