i know machamp is a better attacker compared to gengar sf against SP, but the reason vilegar works so well is that you could use level down. if vileplume were paired with machamp, it has nothing to fall back on until DGX is knocked out. i mean, once pokemon catcher is released you will have a solution, but then you have to think if you want to clog up your deck with it.
the champlume pairing sounds good, but vilegar, a better contender to SP IMO, still has trouble against it. and the main problem being that vilegar has so many resources to keep the lock going.
so if you are worried about SP. Vilegar or straight machamp.
if youre worried about gyarados or anything else, play Luxchomp because it could beat everything