We used to have a Gun class (which was advertised by Merlwyb in ARR). It was called Machinist and it was all about guns, loading your ammo rounds and shooting. It was boring compared to Bard which danced around doing arrows from various angles, especially in Stormblood after the cast times were removed from both. Machinist went extinct, while Bards were everywhere and extremely popular.

So SE decided to revisit Machinist and change them from being about guns to being about a variety of machines and gadgets, as their job name implies. Their rare heated combo was made permanent because its animations were more fun. And after the change, it was extremely fun and it's one of the main DPS I've used this expansion along with Summoner.