Last season I had the same sensation using the team of the OMA League, the Port vale... and the solution for that is sell the worst player that you have in every line, (DC-MC-ST) and try to buy a key player.
I had very good results with the ST I bought because is doing the 1/2 of the work that I need to be in the Top of the league. At the end of the season if I obtain the Title ( lets see what happen, league is so long..) I will say for sure that a player did the 1/2 or more of the work.

Remember always, you can have 11 players in the team, but you only need 1-2 or max. 3 to make work the whole team.