I think it'd be cool if they did the mini game from Resident Evil Zero only updated. I think it was pretty cool searching for a certain type of item and having to collect them all for some awesome items....
'Cept they'd probably have to change the leeches to something else.
If not, It'd be cool if they did the Mercenaries like they did in RE3 in which you had to run through certain areas and do certain things and get to the end alive in order to gain money, which you could use to buy things like infinite ammo...