I kinda feel like at this point, it's the next thing to explore after Allied Races.
That brings on the next obvious question: What races should get which specific classes?
Here's a few off the top of my head:
- Tinker: Gnome, Mecha Gnome, Goblin, Vulpera
- Blademaster: Orc, Maghar Orc
- Dark Ranger: Undead, Night Elf, Blood Elf, Void Elf, Human
- Dark Shaman: Orc, Maghar Orc, Troll, Zandalari Troll, Tauren, Highmountain Tauren, Goblin, Dark Iron Dwarf, Draenei, Kul Tiran Human
- Seigemaster: Dwarf, Dark Iron Dwarf, Gnome, Mecha Gnome, Draenei, Worgen, Tauren, Highmountain Tauren, Goblin, Vulpera
Those are just some example class ideas to clarify.
I know race-exclusive classes are a touchy subject but I think the timing is there for it personally.
EDIT:
Most who've commented so far chose to focus on the lists than what I specifically said. Forget the lists and focus more on the concept of race-exclusive classes for the purposes of this discussion.
I said I think there should be more race-exclusive classes.
The five example class ideas--and I threat that in specifically to prevent what I've read so far actually--are nothing more than that. Examples to be used to explain my train of thought. The provided lists themselves are actually irrelvant but I'm leaving them there because it helps illustrate my train of thought.
Also I know what "Race Exclusive" means. It just so happens in the case of the last two of those five example classes, all of those races could actually work in the case of the last two examples. I do feel fewer is better personally though.