Yeah. The concept of class limitations by ancestry is sound and valid-- with or without ancestral classes-- but the implementation left a lot to be desired. I think there should be a default set in the core rules, but with a sidebar saying that it's not set in stone and umpires/tables should feel free to tailor it to their setting and lore.
As little as I like the Four in the Core in the first place, the premise that every ancestry has access to Priest (almost always Cleric), Fighter, and Thief... with few races having any Mage or Druid, and even fewer having Ranger, Paladin, or Bard... just feels like a wasted opportunity. Dark Sun and Planescape were great about blowing this open, not just adding more options, but restricting them, too; it seems like a small thing, but "thri-kreen can't be thieves; those with an inclination to stealth become rangers" is a powerful statement, especially when contrasted with their xixchil cousins.
Speaking of little changes reshaping the "feel" of a world... try replacing the Tolkien Trio (plus orcs) with goblinoids and half-goblinoids. Doesn't seem like a big deal?
I wholly understand the reasoning behind homogenizing the PC ancestries and humanoid monsters between settings, but I consider it regrettable. Every old setting does, and every new setting should, have its own unique character and the population is a big part of that.
Drow are an iconic part of Greyhawk and the Realms, but they're out of place om Krynn, Mystara, or Athas. Thri-kreen canonically existed on Oerth and Toril before Dark Sun was even a pitch... but they feel weird as player characters there; thri-kreen and xixchil work much better in Spelljammer than they do even in Planescape.
Having worlds where certain things don't exist makes the "D&D Multiverse" more vibrant than having everything, everywhere, all at once.