Stamina is a stupid mechanic. I've disliked it since I returned to the game to find it in here. It feels like a mechanic they shoehorned in to make gunner less useless because gunner is such a terrible class.
They had this idea starting out that every class can do everything, but each class can do something a little bit better. Turns out as crew, the best thing to do better is repair and buffs, and having more ammo types to choose from isn't always useful. Honestly, if not for guns like the Hades, which needs multiple ammos to control its range, and heavy guns pretty much requiring a gunner to have arcs, there would be no reason to have a gunner over a normal engineer, let alone a buff engineer. Some pilots decide the arcs aren't worth having a gunner and have a 3rd engineer on heavy guns anyways. Even with guns like the Hades, there's people who learn to hit with normal rounds at long range, meaning they don't need lesmok and can buff the gun instead.
Squid, Pyramidion, Junker, and Mobula arguably should all run a buff engie over a gunner, and nerfing the buff hammer won't change that because all gunner does is bring more ammos that aren't needed.
In fact, if the buff hammer was removed from the game, three engineers would still be more optimal in the vast majority of the time than having a gunner. Gunner is that fundamentally flawed.
If gunner could have more than one repair tool then maybe things would be different, since the tradeoff in ability to repair/buff wouldn't be so severe. As is, gunner is a fundamentally situational class who is only relevant because of nerfed heavy guns arcs and stamina.
Personally, I think crew classes should be overhauled to carry whatever mix of repair and gunnery tools they want with up to 3 of each class's tools, including 2 of each, an engie carrying 3 gunner tools, a gunner carrying 3 engie tools. This would make it so you could have "gunners" that could sprint, "engineers" who could force arcs, and mixed classes for a balance of repair and gunnery and a bit more nuance to being a crew member and assembling a crew.
However I already know that's not going to happen because of how much of their system they'd have to rework to allow for that, from database entries to recommended loadout systems to tool selection menus.
...
But yeah. I'd like to see testing of reducing hits to buff guns and how that affects buff-engie and gunner cooperation. Makes it take less time to prebuff gunner guns, but at the same time might be OP in terms of giving the buff engie much more ability to have permanent buffs on their gun.
If the goal is to make gunners see play more, buff their stamina. That's their one unique "no other class can do this" quirk, so make it so gunners can use it more often.
If the goal is to just nerf the buff hammer for being good, then I don't have anything I want to say.