I can think of a few things.
-Fix with the frame rate when you kill a large amount of zombies all at once.
- Bigger maps like Tranzit as the new consoles will have more memory (RAM) to run maps on which current consoles couldn't do for Green Run.
-Smarter Zombie AI?
What would you like to see in zombies when it comes to new next gen consoles?
Hopefully they will add more interesting wonder weapons such as the wunderwaffe dg-2 and the acidgat simply because they have 2 of the most awesome looking animations, i wouldnt mind some tranzit style maps BUT NO STUPID MIST!
Before i think of what it would do, i would first listen and watch what the consoles even bring for next gen. My thoughts on next gen gaming are spent, so before i hop on the "i cant freakin wait for xbox 3!" train ill have to hear from the community and people in general to decide if it is really worth it to buy another xbox and to play a zombie game that ive been wasting my whole teenage life on.
With that being said, i would love to see some storyline implemented. Right now im writting a book about zombies and the afterlife and such. As i write it plays out in my head they way a game would go if it was so. Basically your allowed to play the games but when you need to do something for say Richtofen, the rounds of zombies begin. When one player gets eaten he goes automatically into spectator mode. Once all are dead they get the afterlife mode to activate and are allowed to investigate the map and search for clues to what he wants you to do. Once a predetermined amount of time has passed you respawn in the start with the same weapons you had when you died, except when you start you are given another clue and a quote to help. A total of three deaths are allowed before the game ends. As well as clues, you are given three. It would be amazing if they implemented storyline and survival without making it too retarded. Storyline moments occur as survival moments would except e storyline is already set out before you, you just need to walk the right path.
Nice long reply for the heavy hitters in reading.
I'd like to see at least 8 player zombies. More varied zombie animations(not just walkers, runners and crawlers) and better customization options. Some sort of map editor would be a blessing. Take die rise for example and set the map boundaries yourself. You don't like the spawn point. Change it. Or cut that building out all together. Those three features would be enough of a start anyway.