I think it's worth considering that if Chaosium are looking at producing a beginner-friendly, entry-level product, that RQ2 really is by my book the best game released under that name for that particular criterion. Having the setting baked in meant that people didn't have to puzzle out their own world before kicking off, and the game as written did a great job of introducing people to important concepts and generating buy-in.
RQ3 and RQ6 were both substantially thicker tomes than RQ2, and that's without providing any Glorantha content whatsoever. So I can see why in any "back to basics" attempt Chaosium would want to revert to a very basic form as presented in RQ2 and then add things on in a very careful, judicious way.
A game including every cool system idea that has been cooked up for Runequest from publication to now would be a game that is far too unwieldy to appeal to anyone but the hardcore crowd. I like the fact that editorial discretion is being shown here.