Melee weapons are fun but the ultimately lack personality. It would be cool if as you went deeper in the melee weapon skill trees you would unlock special abilities fueled by a new resource called adrenaline. Adrenaline is generated by taking damage, dealing damage and killing enemies. For example blades could unlock a stinger move that lets them close in the distance quickly, bare fists could unlock a high damaging grab move, blunt weapons could unlock a heavy a attach that knocks downs enemis in front of it, etc... It's just an idea I had but I think this could really deepen melee combat and make it more fun and rewarding to actually invest in melee skills.