If ur formation relies on 3mc (many do, cause very strong middle) then u better have more, u can change the entire formation but in a squad with 22 is lot of space. I have 5mc,5 striker, 1aml/ml 1 mr, 1 goalie, 8defender (dc dl dmc dr) 1 amc, all well covered..
But mc are my main player so have more is nothing bad. With full squad u logically have more from some position..