^^^ good idea.
Yeah, the weapon upgrading was cool... but god! There just better not be another merchant in RE5! It would be better to find weapon parts. But I guess a merchant wouldnt be so bad as long as they have a story for him, like his reason for being there, blah blah blah. Mr. Trenchcoat in RE4 just seemed so out of place and stupid, 'cause there was no reason for him being there, and the enemies always ignored him. That always seemed odd to me.
One thing I want in RE5 is the ability to leave your items behind, like in Zero. That's a lot better than discarding your freakin' weapons and having to buy them again or whatever when your inventory gets full. It's more realistic that way, too.
Plus, like I said before, the Reloading Tool from RE3 could be a good idea. Instead of getting ammo from fallen enemies, you'd have to find gunpowder to make your own. That was always my favorite part of RE3.