Gun is part of the lore. In game lore it's basically gunner, but it's called Machinist, so people demand some machines in gameplay.
It's really problematic case, but i would say Machinist has very bad design since 4.0 (well, 3.0 wasn't great either, but it was definitely closer to perfection than now), and 5.0 wasn't great improvement. It feels very cheap, especially because of multitool appearing out of nowhere.
It really needs an actual rework from scratch, i wouldn't call 5.0 a rework.