Yeah, last time I did it we lost the majority of the userbase overnight.
Also as far as I know there is currently no other board software which comes close to providing Vichan's breadth of features.
Also I'd have to rewrite like, all of the frontend and style code.
And we probably wouldn't be able to migrate the posts, which would mean having TWO board archives. What a mess.
Maybe some day it'll be worth it, but not right now.