Well, in 2E Dark Sun they were meant to be assassins, not the "magical music men" they were in vanilla 2E and 3.X/Pathfinder. As a long-time hater of the magical music man (MMM) ideal (just my opinion, YMMV), I appreciated that approach, and still do. It comes down to personal preference - if you wanted to include a MMM-style bard in Dark Sun, you certainly could find a way to shoehorn one in, such as using a variant power source like the Black. Personally, I don't think it's needed. I gravitate toward the original version of Dark Sun from the first boxed set, rather than the post-Prism Pentad version that introduced some of the alternative arcane traditions.
If a player was really interested in playing the bard class, I'd try to make something work, either by modding the class to use psionics, rather than arcane magic (keeping the buffing and sound/language/music-based powers, but subbing in vitalist-style psionics for the spells), or, for players most interested in the jack-of-all-trades aspect, have them be an archeologist, casting as either a defiler or preserver.