So Spears were added in update 18 and they're pretty neat, spears are one of the oldest man-made weapons and a survival staple, but they leave a little to be desired in the OOMPH department if you're not exclusively throwing them. Spears are more like close-up ranged weapons than melee weapons honestly.

Currently Perception has rifles, explosives, and spears in the skill tree, I think moving explosives to Fortitude would be reasonable, you have machine guns and fists there, having explosives would round it out.
Swords would make sense as a perception based weapon, being you need good edge alignment in order to actually land a good hit, and they'd give Perception a good, fairly strong melee weapon.

The stone sword could be like a macuahuitl, with various sharpened stones placed in a wooden holder, the Iron sword could be a simple hand-made sword with or without a guard (you wouldn't really need it against zombies honestly) something a novice blacksmith might make, and the steel sword could look more like a well made sword like a more experienced blacksmith could create.

The sword perks could be in line with the with the Pummel Pete perks but instead of focusing on stunning and knocking down, it could focus on severing limbs (Ex: Extra chance to remove arms and legs) and doing more damage to enemies with severed limbs, and the later perks could give you a buff for a short while if you cut enough body parts off in a period of time, refreshing with more body parts removed.