For my sins, I became very addicted to Shades on Prestel back in the day. Due to this, I prefer MUDs that are not deep on class progression, and just easy fun.
A lot of the still running MUDs have deep learning curves, due to some of them having been running for a good few decades. To the new or casual player, this makes them impregnable.
Whereas I don't think we need to change the beauty of the text based medium, I do think that the genre needs updating to make new MUDs more accessible.... Even D&D finally accepted it needed to simplify again to gain new players.