I say do more. Well, if you want to get cut and have the bodybuilder desired look, two more excersizes should help. Flyes, pec deck, cables.
For strength and size, Id still say do more, but I guess it COULD result in overtraining. Shit, I dont know on this one. Youre already doing 2 excersizes and making gains, would incorporating 1-2 more excersizes really hurt? I suppose its possible. Hmm...someone want to add?