I have Dk + 4 rets and I wish that I had a paladin tank instead. I switched my paladin tank to my shaman group, so I replaced him with a DK. Talk about a headache. Too much clicking on a DK. I also have a mixed team with a warrior tank. Another mistake. Paladins for tanks. Always. It's one less thing you have to think about.
Now should I level another paladin or just switch my paladin back over to the ret team and try the crappy DK on my shaman team? DK even has good gear... too bad they require solo play to be the same effectiveness of an afk paladin watching TV.