Mug is still pretty useful as it both is an OGCD damage dealer and was reworked in Stormblood to dramatically increase your Ninki gauge.

I think the solution to Hyoton is to make it a viable part of Ten-Chi-Jin. It's unfortunate that our highest DPS for that skill is identical regardless of if we're hitting a single target or multiple targets. Maybe give it a potency increase in combo with fuma? Something you'd never get without Ten-Chi-Jin but would give us the option of using it for higher single target damage.