Does the wakizashi still have the AP perk?
I generally think about 2 perks for melee:
Piercing Blades (name is to be discuessed

)
100 % melee or 100 % Throwing
Adds Armor Piercing +% chance when using knifelike weapons (throwing knives, knife, combat knife, wakizashi, ripper, maybe spear)
Heavy Hit (also to be discussed)
100 % melee
Add knockdown +% chance to blunt weapons (crowbar, club, sledge, supersledge, maybe cattle-prod)