Since WW1 with standard rules is considered a positional slog, I don’t think that adding zombies to the mix is going to make the game more dynamic. Its going to create an even more stagnated wall of positional battle. Also, territory control is quite different than the other editions so zombies would have to be added into that mix and perhaps you could do whoever has the most units controls?
The unit pallette is also smaller, which means the tech and interaction between the units and zombies would have to be fixed on a unit by unit basis (planes dont attack zombies, for example, because they dont attack anything).
