:
Maybe they just need to think about introducing characters like Munch yet. Unless they want to make us see only Mudos for the whole quintology (which would be really a bummer tbh  ) |
Given that it was mentioned that in an interview for Soulstorm that the glukkons didn't want the mudokons escaping to the "first-world" to blow the whistle on them; I think we'll eventually see some of the other areas of Oddworld.