[Autumn]

It would but the point was that a lot of sub-type weapons have skills and classes that support them, like handguns with akimbo and katanas with blade barrier/katana power.

Is there any sort of way to incorporate these as skills in a few classes?

[Snake]

Hexer, Tactician and Summoner (the class, not the promos) could very much make use of whips for melee attacking or extra effects.

Hexers could get an effect similar to Borneblood pre-nerf, for whips.
Summoners could get a passive skill that allows them to use whips on (i.e attack) their own Youkai, that only does 25% of the real damage, has 100% hit chance, but 'pass their turn' to them or grant momentum.
Tactician could do the same as summoners, but to other players instead and with a hit chance?

For Shuriken-type and Javelin. Maybe allow a limited use with Archer/Ranger Offensive skills that use a hit check/Longdraw/Bow Passives to affect their range/hit/critical? It's simple, effective and gives a new use for those. (Example of skills that 'use a hit check': Flip Shot, Retreat Flight, Pulling Shot, Snake Shot... Those are all 'ranged weapon skills/tactics' so why not?)

Fans are also odd. They do have some neat scalings, some of them, and can be a fair use most of the time. But if anything, I'd make Dagger Dance work with tome fans for a new play style for some mages or spellthieves.

Clubs. Uhhhhhhhhhhhhhhhhhhh. I dunno. Maybe something in Soldier class that allows them to ignore the enemy's armor with Axe offensive skills?

[Raigen.Convict]

The thought of a summoner whipping their youkai to get them to act is hilariously cruel, I'd add that it also lowers friendship when used but that might be too much.