In D:OS 1 you can in theory steam roll through the game with 4 zombies and the npc would not care one second that you are undead.
I would be fine with the removal of the zombie talent,simply because it is one of the strongest talents in the game.
On the flip side however,I think it would be fun if both custom undead and origin undead would get a source skill which permanently adds the zombie talent to your target,but can not be cast on characters who already have this talent.
If you are a Zombie, does magic armor still block Poisoned status? If so, the Zombie trait could change it so that poison bypasses magic armor. This prevents it from damaging magic armor and allows surfaces to more easily apply poisoned status.
Yes it does,which is why Rain/Rain of Blood + Contamination is the best aoe healing combo in the game - it's available from lvl 1 and at level 4 you can go Global Cooling+Contamination to remove all fire surfaces and cast an aoe heal with a really big radious + by level 4 all your party members are zombies, so we can consider the dificulty of the game lowered considerably within a 4 zombie team.