I'd like to see the old Red Lotus weaponskill from 1.0's launch return. Maybe have it that the combo action off Riot Blade debuffs the enemy with a defense reducing attack, but only if it's combed, or something.

Riot Blade at the moment though, is definitely just a niche weapon skill that serves one purpose (MP regeneration for Flash). It's not going to lose anything by not having a finisher combo off it, but it would be a nice thing to have.