I actually like the interface because it's so very fast to use once you're used to it (after about a week for me). Almost every command can be accessed by pressing 4 or less keys; no finding the right button, moving the mouse, clicking, moving the mouse to the other side of the screen for the next button and so on. Of course, learning the 20 or so most important keys first is part of the learning curve (or rather, learning cliff), but once that's done, it's absolutely worth it.
As for the graphics: Not necessary in my opinion. I currently play with a slightly modified 12x12 version of the curses set and find it way easier to see what's happening than with most graphics packs. A horde of goblins does look very different from a herd of mountain goats and I have no problem finding the dog in a pile of dragons (it's the burning one)
If there were better possibilities for graphics (as planned in the presentation arc, I think), I think, I'd try again. The thing that bothers me most is that many different things use the same tile from a tileset. Chairs and Tables look like part of drawbridges, so if I want to give a chair a different image, there will be random chair-symbols in my bridges. Or if I decide to draw a nice lever for the ó and ò letters, there will be nicely drawn levers in the names of my dwarves - not what I had planned.
But as I said, there's no problem with ASCII-based sets. There's a wide selection and some even look pretty nice and you can always make your own. I'm already like Morpheus in the Matrix: "I don't see the code. I only see blondes, brunettes, redheads..."