With Boomkins being in such a bad position right here is what I think a decent buff would be to increase their dps. Granted it won't change how RNG their dps can be, and the problem they have with movement during eclipse procs, but it's a start.
Modify the Moonkin form talent to allow haste to change the length of their GCD, allowing boomkins to not have to worry as much about maintaining a haste value of 400. This will allow boomkins to have as much haste as possible, while still being able to not waste GCDs on wrath casts that are too fast. Currently, As far as I know, boomkins are the only dps class with such a low 'soft cap.'