I must be pain in the tender places 
There is one issue. Not for me, but for my top 5 contributers it is matter of life and dead — well, that was perhaps too much but they really want this.
Category settings:
It normally shows something like this (on iPad, but you understand what I’m meaning)
Your layout breaks if there is a description or name of category is longer than few characters:
Disabling show subcategory list above… solves out this, of course.
But I’m moving toward using only top-level categories and heavily relying on tags anyway (and then your theme is actually quite suitable in many ways) — so if fixing that would take a little bit too much work and/or you have something more important to do, I’m totally ok if you work with this later.