IMO I liked ZEM for nearly all of those things, but idk why but I always hated the different zombies, ( the ones that give buffs and debuts at the same time) but I did really enjoy the run and gun, it was a really fun way of playing the mod, and I reckon to implement that's into ZAM would be very cool.
Run and gun map: if this becomes a thing, it can't be for a map, I think having it for a vote on different maps, eg for Nuketown, Jungle, Firing Range, and a couple more would make it better. Not available for all maps, but for some would be awesome.