The problem with removing the italics is that they have meaning. Just about anywhere you see italics in the interface, it means something can be done. Tapping on them will probably do something, or long-pressing on it will open a menu. I outlined what I see of the
UI standards a while ago.
For the missing characters in the titles, the workaround is to get the appropriate font loaded. Opening a book and selecting the font will load the font and it can be used in the library lists.
As to changing the font generally in the interface, there might be a patch to do it. I don't use them, so I don't really know.