Almost every character is more boring as a gun character
A pure gun character is the most boring thing in the game, to play and to fight against. They all play more or less the same, it feels like- point and shoot. Every single time a character gets turned into a gun character it feels like they lose so much of what makes them interesting. Just look at Victor, or Lash, or Bebop. Maybe it's just personal preference, but I have so much more *fun* when it comes to spirit characters.
They're also more dynamic to play against. Fighting a gun character? Buy metal skin, maybe plated if they're really an issue.
Fighting a spirit character? Well, spirit resil is also a good start, but for more acrobatic ones slowing hex can be good, and spellbreaker works against burst, etc. Bullet is so much less interesting to itemize for.
I do think there are some interesting M1 characters, but imo they work best when they're hybrid, like non dash infernus, or wraith. Those also tend to be more interesting to itemize against (can buy dispel magic for instance instead of just metal skin).