You are discounting the door that Viper is going to open: transforming weapons.

Monster Hunter has Sword/Shield that turns into 2h Axe, 2h Axe that turns into massive Greatsword, I think there was an MMO exclusive one too. So we could have a new class that uses a (current weapon) that transforms into (other current weapon) and that'd count as a new thing technically

Personally, I'd make a KamenRider/GARO themed class, where the 'weapon glam' that changes is not any gear on you, but the suit you change into for the 'not Enshroud' move. The 'weapon' can be a belt since we don't have a slot dedicated to those anymore. And we know Yoshi-P is a fan of Kamen Rider so I bet he'd be on board with it (copyright laws might have a word or two though)