I'm biased but I personally think that Paladin healers are great.  They are very mana efficient, there isn't a ton of spells so you dont have to get too fancy with your heals, and you wear plate.  I have 15k armor in my PVP gear which is good for a  tank.  

Also, if you have a paladin in this guild you'd be like the 2nd, and since I have most of my gear from kara already, you'd have a great shot at being quickly geared.

Other classes post and tell me why you're better!

(Though, dont forget to spend the time to gear up your main before switching to an alt!)