This is an important discussion to be having, especially in the context of discussing Gunbreaker. Aesthetics are only part of the picture. When new content hits, players are going to be asking themselves why they should take this job. If there isn't a clear way in which it can distinguish itself, people will stick with what they know (WAR/PLD). It happened this way in the start of Heavensward, too.
This doesn't mean that it has to be powerful across the board. It just needs to have something that it's really good at. Right now, I can't actually see what that could be, because pretty much
everything is "WAR's turf". Best mobility and knockback prevention? Onslaught. Most powerful snap enmity tools? Onslaught/Equilibrium/Unchained. Hardest hitting attack? Fell cleave. Most powerful burst window? IR. Most powerful AoE? Decimate. Most powerful lifesteal? Steel Cyclone. Most powerful invincibility cooldown? Holmgang. Most powerful tank raidwide defensive? Shake it Off.
So where does Gunbreaker fit in? Using ammo is an aesthetic decision. What is this job going to excel in? That's the discussion to be having.
As far as theorycrafting is concerned, you can take it with a grain of salt. It's very possible to spend so much time plugging numbers into formulae that you don't actually play the game. I find it amusing that when reality (i.e. actual content) doesn't match up to our simulations, we accuse reality
of being wrong.
I think it's perfectly valid to ask questions on how data is collected and appraised. That's how you critically evaluate things. More often than not, you'll find more rhetoric than fact. And a lot of
backpedalling.