Your correct, no argument from me about odds being better with the mutant trick. .
As for the World #1, they have 6 mutants teams if i'm not mistaken and are very good tactically in addition I would think. What i've noticed is that I don't need to get my tactics correct, I just need to prevent the opponent from getting their tactics correct. If a manager has mutant players, but isn't good tactically, its still possible to lock-in perfect tactics against them. I've lost against team with average players, despite having mutants, so I would know. But if the manager with mutants, is good tactically (or even just decent), not much can be done. If a one match scenario, sure a draw/win might be salvaged, but over several matches the quality will be too much.