Hmm...
I don't think this bonus is needed. Moreover because being casual I'm almost reaching my 50. I didn't want to reach 50 because I didn't want to, but then I remembered I have another character in the server (The Duke). I took a few days of gameplay to reach 49 and gaining experience in the game now is pretty easy.
I will accomodate this bonus if casual players will find it hard to level up their classes. If they don't, I can't see the point of it.