Who needs ragdoll physics and bump mapping when a few lines of well-written text provide all the imagery you need?
Well, i think you are a bit off here...
At first i thought this would be exactly the same question as "Who needs movies, cg and special effects when a few lines of well-written text provide all the imagery you need?" - Well, i don't think that the relation of films and books is some "either-or" thing... There's nothing a movie can show, that you couldn't also describe in a book, but the way a film delivers this information is quite different. Especially when it comes to describing the feelings of a character, a written book has quite some advantages to a movie, since describing emotions is a bit easier than depicting them. Neithertheless you can't say nobody needs movies, since you can do that all through words alone.
Movies allow expression through colors, sounds, imagery. This can be used to create a dense atmosphere or even for art, in a way you couldn't do with text.
In the same way you can't say that now that there is film, books are done for... I believe that books won't be gone for a long time to come. They will continue to coexist with the movies, and stay an artform of their own.
Well, at first i thought it was the same thing with text based and graphics based games, but then i noticed i was wrong. These games described here, don't use words to describe and explain a scenery, like a book does. A text-adventure like Zork would... But these MUDs and Roguelike games are using the ASCII character set for some sort of graphical depiction of a scene. So they are not to be compared with books, where words are used to stimulate your imagination, without giving you any visual representation at all.
These games to give visual representation, they are focused on graphical depiction, they are not using words to describe... So they are graphical like games with shaders, bump maps and physics, just in a technically limited way. Heavily limited way. Games back then didn't have any more possibilities for graphical depiction, and the way they used ASCII to "paint" images with it is a really ingenious way to overcome these limitations. They made a virtue out of necessity.
Now that the necessity is gone, what's the reason to keep up the virtue? That's the point where i always do get the feeling, the arguments are getting kind of "religious". For someone who isn't tied to these games by feelings of nostalgia, it will be impossible to understand why you should use ASCII, when you can have physics and bump mapping.
I don't want to say, that these MUDs are "bad" games. I truly believe that, since those games didn't have the graphics, they had to focus on different things, like story-telling, plot, etc.
Nowadays the focus lies on hyperrealistic graphics, and the newest special effects, graphical tricks and visual polishing is so damn important, that most other aspects of games are getting lost on the way. All those great big successfull games feature stunning (and most expensive) graphics, but little else. MUDs may be better than that, when it comes to story-telling and plot, but not because they use ASCII. Not because they implement those old virtues that were made out of necessity back then, but have lost their reason d'etre since those necessity doesn't exist any more.
New blockbuster-Games do not lack Story and other Aspects because they use bump-mapping, shaders and physics... It's all because of the money. Making Games with newest technology has become quite expensive, with costs comparable to Hollywood film productions. And if you don't invest that money, your game doesn't look like a low-budget independent film... It does look like a b/w silent picture... The gap inbetween the massproduced shallow blockbuster-games and independent low-budget games is enormous. That's the problem.
This brainless mainstream factory-ware (with it's endless stream of totally un-innovative sequels)is exactly equal to what you can find in the movies, or in the music genre. But in difference to the film- and music-genres, within the game genre, underground productions absolutely can not compete quality-wise.
When it comes to music, every small unknown band cand produce a CD in their cellar. Audio quality may not be as good as with professional equipment, but for the uneducated end-user the difference will be marginal.
When it comes to film, B-movies do lack special effects, explosions, cg-grafics but normal scenes just showing actors against some backdrop... these don't differ much from any billion-dollar-production.
But when it comes to games, underground productions feel like riding a horse-carriage with broken wheels, whilst everyone else is driving a porschee or ferarri.