I was Boomkin in Cata. The extra DoT splitting Sunfire and Moonfire killed it for me.
Elemental Shaman is so much easier to manage with a lot fewer spells to worry about. Ascendant is like a super burst, feels-good-man spell if you have ever seen it. Pretty much guarantees your strongest spell to crit all the time, coupled with Lust, it's a machine gun.
I'm pretty much seeing that and BM Hunter as my two options. Both have their ups and downs. I think BM is a blast to play, so I probably will just go with that since I want to be enjoying myself.