Well a simple and quick solution to fix the mutants is not to permit the program to see them as mutants.
What does it mean ?
- Remove the white and grey skills.

- All the skills will have some connection with the gameplay.
A ST with 1% defending skills, will offer 0 to team's defensing line.
Also with 1% fitness, after 60'-70' min his performance will reduce dramatically.
A DC with120% general quality but 1% speed, will have a serious problem to face opponent attackers with 80% gen.q and 90% speed.

Can the devs do that ?
Don't know