I dont mean to derail your thread, and I fully respect your reasons for going back to single boxing - but I see its quite a trend and for some very active boxers here.

I did what alot of you are planning to do back at the start of Wrath. I tried to play my Paladin and 4 Shadow Priests and it just didn't work well, I got disheartened and went to single boxing for many months before levelling up 4 shamans when you could level through PvP and had a geared out tank. I remember heroics where not easy as I lacked hit and other things, but my tank could take a beating.

The one thing I'm most excited about Cata is the new challenges to overcome as a boxer, and to be doing it on day one - to have to learn to effectively use CC, to use the advanced features of ISBoxer or JMB to their fullest. To be one of those people beating the content at its current Tier, not coming back in 6 months later or waiting for the Niley's and the youtube videos or to overgear it.

I'm looking forward to discussing and debating over strategy and makeup in the PvP and PvE forums and seeing these forums come back to life and hopefully show a bit of their former glory from the older days.

But to your original question if I had to pick one thing, I'd pick the same thing again:

I'd suggest Paladin because I'm biased and originally when I started boxing back in TBC, I wondered why I'd never played one before and it became my main and always will be.