Y'know, the reference to IVAN is a good point in favor of graphics.
I bet we'd see more good points if the graphics crowd had a few more people willing to spout ideas rather than flame.
Living proof it could work out...though IVAN is also alot simpler than DF. It also happens to be another inevitable march to destruction, but I suppose that is beside the point.(Why must I suck so *hard* at roguelikes, yet love them so? IVAN, baby, you're so cruel to me.)
One concern, though, is that IVAN's tiles were *big*, as I recall, at least as compared to most RLs. This would be problematic in Dwarven Fortress stretching for leagues under the mountain, I would think...maybe a 'zoom' function needs to be implemented if we ever get big 'ole purty tiles. Let us zoom out, move over(perhaps with the mouse!) then zoom back in to observe our poor, mortal servants from up close. This would allow us to look around, and it'd allow for a graphical tile that you could actually *do* something with.
I like the UTF8 idea. There was talk around the ToME forums of switching to that, I believe, last time I was there. Been awhile, might even be using them by now if the idea went through. ToME is a pretty complex Angband derivative, and the sheer volume of *stuff* was pretty impressive, so taking cues from that quarter might not be such a bad call.