The main perk of Xenophage is called Pyrotoxin Rounds. I understand the pyro part given it's a solar weapon. But pray tell, where's the toxin? Xenophage should apply poison to any targets that don't get one shot by it. Maybe even reclassify Xenophage as a Weapon of Sorrow so it can benefit from Necrotic Grip. Rangefinder should also be replaced with either Field Prep or Vorpal Rounds, and the catalyst should grant the perk that didn't make the cut for replacing Rangefinder. That way we get more ammo and more damage against bosses. Of course, I'm just a filthy casual, so what would I know about making weapons more fun to use?