7dtd, except with monsters insted of zombies, this way they can really get creative with the creatures that inhabit the world, you can even include zombies as well as they are technacally a monster type. Locking 7 dtd to zombies imo really has limited what could have been done with the things we can fight, especally with all the zombies bascally being carbon copy clones.. I accept the carbon copy zombies now because optimizations haven't really been done as its alpha, but once they hit beta, these current zombies won't cut it. I'd also like a borderlands/diablo-like gear system with randomize stats on gear and such, even on crafted stuff. Could have a situation where this armor has an awesome buff, but in terms of actual protection its on the low end to balance the buff it grants.
TBH I was never a big fan of the gpsing horde every 7 days, The wandering ones sort of fit the zombie theme more, they don't gps, but walk in a pile near where you were/are.