Could go either way IMO. Slade is stronger and has better base durability IMO. Wade is faster and heals better. Both are strong enough to hurt each other with their standard gear, considering Mirakuru soldier flesh was compared to concrete by Felicity (after Oliver bent one of his arrows while stabbing one of them), and Wade was able to stab through concrete with his sword in the first DP movie. And, obviously, Slade's sword will have no issues cutting up Wade. Decent match up.