blood DK is alright. I felt warrior is the best tank now, with paladin coming in 3rd (no experience on druid tank). Somehow warrior just takes much less damage overall where my paladin's HP drops fast (could be just shock waves,). I guess that's how they balance tanking class/talent that doesn't have mega self heals.

what happens in between 60-84 is deceiving though. Once you go into cata instance, you will see the trash mobs drop much much slower. and your biggest heal can barely fill up 10% of your tank's HP bar. At 60ish , I can heal tank to full with just holy shock (from 15% to full). At 85, my holy paladin can't bring anyone back to full, all at half HP. This is where I felt priest would outperform shaman. Priest's shield/hot/aoe heal are just more efficent.