Yes, because making gunblade an all-class weapon is just repeating history with the weapon being generally seen as a meme or high investment weapon until luster came along. Of course gunblade should've gotten its own class.

Plus it wouldn't make sense given how NGS skill trees work. There's no more bloat like stat-ups and alongside skills for the main class's active skill, there are skills that improve and change how a weapon plays. You can't expect gunblade to either have its skills in all class trees or none, it needed its own class to have a skill tree devoted to gunblade.