I have won trebles too. And I do not believe in what you say. Otherwise the training trick (Give 1000% speed/fitness to a player and 1% in the rest) would not work. I think that stars are one thing. And performance another. I believe in the first not in the second. My team is PERFORMING better with a 7 stars player getting a 6 rating than with a 4 stars getting 10. At the end of the day, high-starred teams win trebles. Not the others. In general, I do not pay much attention to my players' rating. This is BS. It may be indicative if you compare 2 players of similar quality. But a 7 stars will always have priority in my starting 11 over a 5. Nevermind the "performances". On the other hand, I believe in morale, bonus and (still) in tactic. But less and less in the latter.