Not sure if it has been mentioned before, but here is an idea:
Give Zombie a new ability, CLS style, that allows her to switch between a "Tank Stance" and a "Paper Stance"
Have the Tank stance be as strong as the gear and mods you have on her, and the paper stances with fixed stat equivalent to a low geared one.
This way you can get benefit from gearing her up when you need a Tank, but you can also haver her become fragile to make use of Daka's Zeta.
I think it's a simple solution that would create an incentive for gearing her up, instead of punishing for not doing so.