Punch and kick are the only viable melee option right now, so we don't have to make it better as well. The problem is melee weapons are sucks, NOT the physical attack. The melee weapons are sucks just because basic melee options - punch and kick - are simply superior to the weapons, while weapons also requires slots and tonnage to wield but punch and kick just requires functional actuators.
The only exception is Talons which makes kick to insta-kill button against most similar to lighter mechs on sight(with TSM, only one kick can melt all the armor and barely leave the internal leg structure against fully armored mech with same tonnage, so if it was somewhat damaged it is sure that the leg would be gone to history by only one kick attack), but hey, that's clans exclusive option. Although it is silly that it is clans only - can't we just make a bigger claws and put it on the foot?
Honestly, what if a mech with functional hand actuator can wield a melee weapon for free, as if a handheld weapon but no needs to spend two hands and do not interfere weapons on torso, arms(still you can't shoot and physical with the same arm on the same turn, though) and head. Sword needs more love to be functional though. But perhaps it would be somewhat out of topic.