[gchpaco]

TeX was the first serious examination of what good typographical layout was and how to codify it. Previously there were many rules of thumb, and lots of examples, and a handful of programs for typesetting (like RUNOFF, which was and is pretty damned ugly, although it beats the pants off a typewriter) but in TeX Knuth created an algorithm for things like mathematical layout, for paragraph layout. I am unaware of anything that has surpassed TeX in this field—programs like Lout use the same algorithm TeX does, just with a less idiosyncratic surface syntax and with a rewritten core.

[amichail]

TeXmacs has a typesetter with real-time WYSIWYG editing that is comparable in output to TeX. So TeX has been surpassed in that sense.