User blog comment:Kogath/Monster Hunter X Discussion/@comment-26953474-20150606201745/@comment-25275196-20150618062109

I like the old areas, but it's unlikely they'll return till 5th gen or evn later, all of the 4th gen areas were in the demo, along with the new one, forest and hills, snowy mountains (BEST AREA EVER), and the misty peaks, since these are the key areas for the new villages, I don't think we'll see any others.

P.S. I have a theory that all of the key areas can only be accesed through quests in the respective village, if you know what I mean, and the 4th gen areas will be the basics used in everything, except that the frozen seaway should not be accesed in pokke, the ansesteral steppe should not be accesed in kokoto, heaven's mount should not be accesed in yukumo, and the pimal forest should not be accesed in beruna. (but all the areas should be online)