I never thought the ASCII graphics were a big problem in Dwarf Fortress; once you get used to it using a bunch of symbols as decoration, almost all the weird stuff ends up being things you placed yourself. On the other hand, the complete lack of UX consistency - whether a given submenu will use primary/secondary cursor keys, nested menus, or a pile of hotkeys - is a lot harder to deal with.
I completely disagree. The ASCII "graphics" (if you can really call them that) are a huge reason why I've never even considered playing it. I've read all about the mechanics, and they're interesting. I just don't understand why anyone would spend so much time developing so many intricate features when the presentation is so poor.
While I cannot speak for the developer, I can understand why they would go that route. Unless you have an interest in computer graphics, implementing them can be dreadfully dull. Unless you have an eye for design, creating the various graphical elements can lead to some interesting results.