I wouldnt say for assists and kills, atm you dont get zombie assists (i think it should make a return imo) as this will simply buff peopel who are more skilled, horde resistance will be implemented which should help, id say not much needs to change about normal zombies currently, theyre retty well balanced and since fagstie and howler unlock pretty early on and are already very strong there would be no need to have a normal z buff, plus you get poison and charred in late game which effectively replaces the normal zombie during that phase
that being said the 1 thing i would suggest is allowing flesh nests to be set up in much smaller areas, currently you can only use them in wide open spaces making them useless on half the maps as you cant put them in buildings or alleyways, Id also suggest a decrease on the distance form humans to spawn on Z as it seems the radius is so large atm that its pointless, these both arnt game breaking and arnt the end of the world if they arnt changed (so low priority on the to do list)