I think the lack of controller customization for active abilities sometimes makes a negitive impact on gameplay. One of the problems is procing a synergy at the right time, for which I assume PC players have a deticated buton. On console pushing 2 buttons simultaniusly sometimes creates problems with the system recognizing one button being pushed before the other. Often a synergy proc gets missed because your charecter is fumbling around using their active abilities. While it is possible to put targeted abilities on the synergy buttons, it still winds up being clumsy when you have a target.
What I propose to fix is that a synergy would can be procced off the combination of L3 and R3, because as in the case with dropping an ultimate (L1+R1), or doing a bash or breakout(L2+R2), each hand has the combined focus to push the buttons simultaniusly, instead of clumsily mashing circle and triangle (ps4). In addition, you wouldn't even need to move your thumbs off the joysticks.