Trap stacking would be pretty imbalanced hahaha. Stack enough traps and you'll 1 hit ko anyone, even paladins. You'll just have an army of trappers in WoE.
That said, I think the pneuma idea is good. +1 to that.
Snipers don't really have a way to counter pneuma currently. Ganbantein would definitely be something that isn't game breaking - casting it takes longer than pneuma takes to cast - but yet helps massively in this aspect.