No I am not talking of match bonuses, am referring to those pre-match trainings 2 or 4 of them depending on how much time till the next match - they are very crucial.
The game generally weighs all your trainings, including those for bonuses, if they are not balanced, the imbalance will reflect on the neglected area performing poorly. That is why you can buy a good defender but will perform poorly if and when he plays at a time when your defence hasn't been trained effectively.