The main problem is that Kemuri is bad except Saigai. Same thing with Kudoku. I think that there are the most popular characters ever and they still aren't changed. Skeleton Key is a great item, but I guess that people will still prefer to use Saigai to Sainan even with her clan item.
By the way: You forgot to add in Skeleton Key's description, that:,,This item can only be equipped by Sainan, Saigai and Arasoi.''
I can't see it both in forum and in game. :)
There's also a mistake in Warbanner of the Shogun's description on the website. It says that ,,When the holder performs...''.
I hope that it will help You :)
My ideas make WON a better place, so like them and the mods will make them happen!!!