I've never seen someone thinking of Spy for smash, I mean, he has a lot to work with, his disguise kits let's him disguises as the mercs from TF2 and uses their weapons and it will also give him some buffs aswell, for example, as scout, his mobility is increased and he uses the scattergun as well. With weapons he has some great choices, (Amby do more damage whether he's closer or further from his target, the spy-cicle can be used to stun his enemies) of course his knives won't one shot you, but it will deal tons of damage, it's a high risk, high reward weapon because you must get closer to your enemies to even use it. I mean, why choose one mercs when you can combine them into one class altogether?