The Glen
Legend
That would be the logical choice. They used Holloway as the principle artist and its hard not to go silly with his style. Granted nobody did facial expressions as well as that man.I would like to see an "Orcs of Thar" written from a more serious, more modern perspective. That whole Gazetteer was problematic from cover to cover, but there were nuggets of good stuff hidden in there that could make for an interesting campaign setting or add-on. If not WotC, maybe Goodman Games could put out an updated version, much like they have done with some of the classic Mystara modules? They're one of the few publishing houses that I would trust to get it right.
Off the top of my head: they could get rid of the cartoonish artworks and silly names, and replace it all with crunchy mechanics, timelines and backstory, new maps, new art, and tons of lore on the environment of the Badlands. They could rewrite the orc and clan factions with more modern sensibilities, and like the petition suggests, just drop racial stereotypes wholesale--they contribute nothing good to an otherwise interesting product idea. They could even keep the board game, provided they could eliminate (not dilute, not "tone down," but utterly destroy) the racist tropes, imagery, and names.
TL;DR: Doing this the right way would require a complete rebuild, not a mere "cleanup." It should be unrecognizable from the original, because (flips through the original, gesturing widely).
Mystara is about fantasy versions of real world cultures. Only picking out the ones that depict minorities is a bit disingenuous since they did it to quite a few other nations as well. The Hattians were cartoon Germans. The Ost-Dook gnomes weren't even trying to disguise the fact they were Belgian parodies. Cimmeron is stereotypical Texas as imagined by other people. Nobody is demanding these nations being rewritten.
Want to rewrite the book it doesn't reflect the TSR silly phase? Fine. I have reasonable rates. But people needs to remember what's offensive to one person isn't shared by others even of the same group. You can easily revise the book and say the orcs steal the cultures of those that have defeated them in the past, which is mentioned in the Ethengar book. You still keep the humanoid threat and they keep the trappings of the human cultures but you remove the humor. Problem solved.