I remember one of the first posts I read on the Ro1 forums was about how suppression didn't work. I could understand the points made but at the same time there was a common agreement that when bullets were going past your head, it was hard to make a shot back. The problem was it wasn't very long term.
My favourite solution would be a mixture, blurring of the screen for a long amount of time (ro2) + "SNAP" of bullets with blur (simulating the instinctive closing of one's eyes) + Jerking movements, to stop you from being speedy and just popping up and taking them out first.
This would all work hand in hand with higher weapon sway, taking away the method of the quick headshot, which is just too easy in Ro2, and lengthening the firefights while putting an emphasis on cover.
(Oh, and I forgot to add that there are too many hero weapons, annulling any idea of a long term firefight, lessen that number a little and make the team 2/3 riflemen and MG will suddenly become a feared class)
