When I used to play WM I used the shirokata as well because I found it aesthetically pleasing.
This was back when the shirokata was worth around 40k because it wasn't a relatively common drop from Land of Iron.
It was already a lot worse than the Bone sword and Blood katana.
That being said,
With shirokata being a mid tier weapon with relatively high stat requirements. It's in a sort of no-zone where even if you did lower the requirements there's already so many weapons that you can alternatively use.
I know it took a long time for the Muramasa sword to get reworked and before that happened Rory had stated that he wouldn't balance it until it made sense to do so.
I suppose my point is,
If you're using a weapon for It's looks that's perfectly fine. But don't push it on Rory to make it more viable any sooner than he's ready to work on balance changes.
Since lately he's been working on things that are a lot more important to the game than balancing a mid tier sword.
(Reworking the log in system+the new client with Wolf)