It feels like snipers out of all the fighting styles are quite underwhelming at the moment. So I'd suggest an indirect buff. For people using long range attacks using the slingshot a good addition would be adding a whole array of ammunition, there is no better (cannon [pun intended]) solution than adding pop green to the mix. For the trade off of having to grow it yourself you get varied munition you can use in varied ways.
Few examples: BANANA BOAT, trampolia, bamboo, exploding, sleeping etc.
Besides the munition addition I'd like to see more "utility" sniper moves. Like a sniper move that makes you shoot way further or add a sniper move that shoots extremely fast but not as far. So use sniper move x and it will apply next shot you make.