Not Polarizing for 'D' Polarity allows you to keep build versatility, since 'V" polarity mods are usually much better and not many 'D' polarity mods are strong. So unless you plan on keeping Healing Return EXCLUSIVELY on every config, there is no need to Forma for it's Polarity

TL;DR

1. You can replace Organ Shatter with Amalgam Organ Shatter if you are a Heavy Attacker enjoyer, of course, no problems there.

2. If you don't necessarily care for highest Crit Chance, Blood Rush can be removed for Condition Overload for a BIG damage increase or Carnis Mandible to up the Slash Weight on this as well as the Status Chance. Same goes for if you dont care for the extra Crit Damage, remove Gladiator Might instead and replace with either Condition Overload or Carnis Mandible

YOU CAN ENTIRELY CHANGE THIS BUILD BY PUTTING ON VIRAL + RADIATION + MELEE EXPOSURE (For Corrosive) TO GET EVEN MORE EFFICIENT HEALS FROM Healing Return