I think any Primary weapon that falls under the "scatter projectile" classification for the armor targeting mod (Autos, SMGs, Pulses, Sidearms) should have access to Overload/Piercing and any precision Primary (Scouts, Bows, HCs) should have access to Unstoppable mods.

Right now, theres no reason not to use Recluse for anything with Overload or Shielded Champions or a Hand Cannon for Unstoppable Champions, which really restricts the PvE meta for high level PvE, and further stacks the deck against weapons like Scouts and Bows.

Maybe Snipers could get Shield Piercing, Fusions could get Overload, and Shotguns could get Unstoppable too.