I have no clue on DK/Druid/Paladin tanking at 85 - or well, I tank 10 mans with a DK, and even at 80 I had clue only of Druid and Warrior tanking. Seriously though, warrior tanking is easy as hell. Druid tanking at 80 was easy as hell too. I can basically smash my hands on a pile of abilities and succeed if the boss/trash mechanics are tank and spank + I need to keep track of Shield Block, Thunder clap and Demoralizing shout, but they all have 30s duration or cd so whatever, not hard.
Warrior tanks have tons of utility you can use in some fights, like adds on Maloriak, but they don't really make the class hard. What shockwave/heroic leap/intervene/intercept/intimidating shout/charge do is make me want to play warrior since there's just a ton of more interesting tricks I can do compared to what I could do back when I tanked with my druid in WotLK instead of faction changing the warrior.