Hey man, sorry for no reply, thought in it but days passed xD
But for my side and for what you explain, you are in a so, so close league if 2-4 have 1/2 star more and the others, 5to7 -4/5%, your scenario s a league with practically all teams in a differance of half star, and thats not differance really, as the internal proggramming of a single player of the worst AvQ team in this situation can perfectly overcome the entire rest of teams of your leagues and make the differance if is a key player.
Understand that if you ask for a solution, to try to reach the top in your situation, even Ive played almost 5 years I dont have the key. I just can suggest you, apart from what you know, play with win bonus and training bonuses, try to find a key player, if you don't have one, and powetrain in some young players and the decisive ones, skills as the speed to overcome easily the 1vs1's and have more easy to make the differance.
But have in mind that the differance between your teams in the league means nothing, so the winner will be the one capable to find the most effective and determinant players despite have the same quality as the other rivals.