It could be interesting, but probably better if it’s less an actual zombie and more of the zombie-like traits of cataclysm zombies while being burdened by a still living human body, or something of that sort. Maybe a body that has a bigger blob presence, perhaps in terms of volume, which leads to a more flexible (and unsafe) mutations.
Off the top of my head, some possible mutation ideas:
-acid spit, much like the spitter zombies. Activate and fire; damaging projectile, and easy zombie corpse removal. Catch is that acid coming out of your mouth is painful. Head damage and pain, will cause you to get hungrier per use. Or you activate it, and it’ll give you a very fast metabolism in exchange for firing off acid spit.
-blob body. Getting hit will remove chunks off your body which can release random blobs that are friendly to you. Maybe a lowered defense since parts of you can easily fall off.
In general, stat-losing traits would seem fitting. Like Hulk-like traits will make you dumber, or less dexterous in exchange for a bigger boost in strength. Think prime/extremely strong, with much higher strong and a big drawback on another stat.