Even though I don't roar/howl much, I suppose it would be a cool idea for those who do.
I don't think it's a MASSIVE addition to the game, but yeah, its alright.
Just a thought of mine, I wish the roar action wuz a bit more, ummm, "Liony".
I don't know if you can alter the sound in the settings, but the roar seems really quiet compared to the howlin'.
Anyway, better not got too off topic.
If your idea ever happens, lets just say there wont be anymore spasm-moves like when your char is lyin' down and then you suddenly rawr/howl, which makes yer stand up like a stupid mushroom.....