Mechanically (yuk yuk) Machinist does play rather nicely, but the damage aspect is meh. Being out of GB still feels like it plays a lot smoother than being in GB. The biggest difference I have seen so far between WM and GB is that Gauss Round is a freaking instant cast EA. What the fuck. Still, GB seems super slow, the proc issue rears its head way more with GB, and it's probably just me, but Rapid Fire does not jive well whatsoever with my Wildfire rotation with GB.
WM you are rooted or at the mercy of Straighter Shot procs. Those are your options, unless you want to spam Feint like it's going out of style (and if we count Feint spam, MCH gets it too.) It's just bland. There's no depth to the class, no planning, no control. It's pure RNG in all the worst ways.
GB gives you a few tools to deal with things. You can proc fish if there's movement coming up soon-but-not-now. You can bank procs on 3 and then 2 to ensure you have an instant-cast handy without wasting any potential future procs (vs sitting on Straighter Shot, where every Heavy Shot you do with it up is a potential wasted Straighter Shot proc); ammo gives you guaranteed GCDs for movement, ditto Rapid Fire. There's a lot you can change about the MCH rotation to cope with movement, especiallly in FFXIV's insanely scripted boss fights.
Basically on MCH if I'm stuck rooted somewhere mashing one hoping for RNG to bless me, there are probably a few choices I made along the way to get there. On Bard it's just praying for RNG all day every day. I do think Reload/Quick Reload need slightly shorter CDs because the stretches in between are a little too long, but MCH I usually look at an encounter and think there are things I can do to deal with it. BRD is just deal with turret mode or eat the damage loss from turning it off.
I used to use it to get to the procs super quick to hit my auto crit fully buffed Clean Shot, but now I end up wasting like 1-2 GCDs insta-casting instant cast procs. Any tips, Angary-senpai?
They're not wasted--you're shrinking your GCD for the instant-cast procs, too, letting you fit an extra GCD-ish into Wildfire. I do go against max DPS/conventional wisdom (surprise!) and sit on Rapid Fire when I know I'll need to move, or if I want to Hot Shot/Lead Shot/Get my first proc really, really fast after a jump phase, but using it in the opener isn't really a waste if you can gain an extra hit.
My MCH opener is hot garbage right now, though. There are somehow more buttons to hit than bard, the Wildfire timer giving a massive punishment for missing something, and then Rapid Fire messing with oGCD weaving for those GCDs.