I so agree with OP. Pointless change IMO.
We had Roland the Soldier, Axton the Commando, Wilhelm the Enforcer, and now Moze the Gunner. Roland, Axton, and Wilhelm had a pretty similar core concept: all around DPS and survivability with no game breaking gimmicks and support deployables.
Moze doesn’t have a deployable because the mech is not independent of you. That already massively separates her from the prior 3 soldier classes (and honestly, I’d say Zane is more of a soldier class based on his skills) so having a nondescript name like “Gunner” doesn’t clarify anything. It just makes her sound really generic.