First of all I would totally remove the current weapon system, since it doesnt synergy well with the concept of having many classes with different weapons. Swordmans are especialy prone to that problem due to weapon restrictions on skills.
IMO the best solution would be introducing some kind of goddess given item, blessed artifact, that can take a shape of any weapon at user will. Meaning no more weapon types, the artifact give you the power to wield any weapon at any time, shifting automaticly inside battle.
Then just add some gems/crystals/whatever you name it, which you can find everywhere in order to slot them into the artifact to modify it: boosting stats, choosen skills, playstyle and even appearance of the item when it shapeshift etc.
With this you automaticly resign from +'s and trascendence system, since it doesn’t fit something like that. Also it will add more depth into the game because you get possiblity to customize your weapon.
Additionaly it will reduce the budged needed for animations - if your weapon shape shift to anything, you dont need to do seperate skill animation for different weapons or restricting yourself to create animation that will fit every weapon.
It’s WIN - WIN solution.