Man this REALLY is a tough one...my heart says Cap but my mind says Deathstroke.
Cap is brawns + heart
Slade is brawns + brains + healing factor + firearms expertise
On paper I'd say Deathstroke...but of course many heroes have been shown to defeat enemies that were way superior to them.
Eh...Slade gets my vote for the reason below LOLLL
http://www.youtube.com/watch?v=tdK5pz16SnE