the snake fight really sucked. pretty much any cocoon mutation miniboss fight is more fun to play in.
RE6 is better than all past RE games in only one area, that is the combat system. counters, finishers, being able to jump backwards left right and forward, mercenaries grenade glitch. the combat system is really the only part that surpasses all past RE games.
RE5 has better story, RE6 tried to do 4 stories and took on more than they could handle, rather have less stories and longer and fun stories than 100 stories that are shorter. far too many chase scenes in RE6, Re5 had a vehicle chapter (the jeep) but that was that one chapter and you never really get forced to do another poor sequence like that again, RE6 just threw it again and again at you in the 4 stories. helicopters jeeps bikes sportscars jets screw it all.
RE5 also did the inventory and storage system better. i like choice. if i want to play Ada's campaign with only the wing shooter and semi-automatic rifle i should have that choice. here in RE6 they discarded the grid inventory system that was great and easy to manage and force you to carry all the weapon, if you skip picking it up they deliver it to you and the end of the chapter. also no weapon upgrade system, that made playing RE5's story the first time simple or difficult depending on decisions, i like the little upgrades that showed how much you know about enemies and combat when you are first starting out.