I think you might want to try out feral if you don't like long casts. Balance is fine as it is Because starfire is such a long cast, it has higher damage per cast time than wrath, that's the point of it. You have to stand still for longer to do more damage overall.
If you don't like cast times, play feral -it's quite viable for leveling as well.
Always disliked feral leveling simply because of the fact you could never get a full rotation off on a mob. Made me feel kinda lame. Boomkin lvling was really slow as well, but better due to multi-dotting.
But yeah, even the Starfire damage is kind of weak. Starsurge does more damage than starfire which is pretty lame in my opinion.
if you feral level you never get a good rotation off indeed, i usaly enf up mangle, rake, mangle, FB
as for boomking, the cast is indeed high, you could thoraticly stack haste gear, but thats not avaible at your level
maybe try and go for a multidot statigic, dot up many mobs and run?
If you are leveling with enchanted BoA's good luck getting any kind of rotation off. Even in dungeons a boss dies super fast. as for the slow cast time it becomes much faster with increased haste at higher levels. I dont know if I would bother cycling threw eclipses while questing probably just sunfire moonfire wrath repeat.
The shitty part of boomkin and low level dungeon is that unless u stop to align pre-eclipse you most likely won't have Nature's Grace up for most fights. By the time you manage to rotate into a new eclipse (which would've given you the haste buff) the boss is dead. Not sure what lvl do you get Celestial Alignment, but even that sucks cuz you can't do it on the move.
Feral has a bit of ramp up but not a lot imo, it also has some pretty reliable aoe and that can be cast on the move (which is perfect for quick low level dungeons). U just keep running spamming ur aoe. You can't hurricane on the move.