To not lose the gameplay aspects of the abilities it would be interesting to see them as in-round regenerating one time pick-ups to provide strong temporary abilities. Possible balancing of these abilities and other pick-ups could be the need to switch from your primary weapon to the ability to utilize them. This would also indicate to other players that you are about to use a powerful ability, and would be in-line with the utilization of power weapons. Otherwise a simple button click to activate an ability could suffice. Classical arena- and casual modes would likely play very well with ability and power weapon pick-ups, while they could come at a detriment to tactical gameplay in the more competitive modes like bomb defusal. Testing should probably be conducted for these cases.