The mutations available are very weak (specially compared to cybernetics) and the time gap to develop new tiers are long (again, specially compared to cybernetics).
The mutations "stats" should need some changes and more options.
Another interesting options should be "mount attachments" to mutations like tentacles (paralizing or draining) torso mount weapon.
Basically, mutations are very limited and compared to their equivalent armor (and cybernetic) are very restringed.