I hate him too, I liked him in PoR, people say it is the other way around and that he sucks in PoR, c'mon, he has awesome growths, he got slowed down in RD, his HP growth halved and his Def growth got decreased by 15%.
When I get RD I'll get him killed by endgame since you can.
I wouldn't kill him, personally, since it's MUCH too late he has to be there for the endgame anyway.
It's a shame... He seemed interesting in PoR, but they just turned him into a whiny little (insert 5-letter word here) in RD. D: