People seem to have different opinions on what truly defines a roguelike. I think that ASCII-based graphics are one of the most defining features, seconded by the sheer randomness of the game. I'm here to discuss the former. :P
As many of us already know, BYOND's textmode can display both foreground symbols (letters) and pure background colours. Obviously foreground symbols are more rogue-ish, but the unique background colours that BYOND supports are a very nice features that I'm not sure I want to give up.
While the foreground symbols stay true to their Rogue heritage, the background colours can really flesh out the environment around you. For comparison, look at Volte's demo of background colours compared to mine of foreground symbols.
What I'm trying to do is determine what the best path would be for an ambitious roguelike being developed within the constraints of text-mode. I look forward to hearing your opinions on the matter. :)