>>32763056No. "All regions" is already silly to begin with, but even if Gamefreak considers it a legitimate idea it is a goal out of their league to attempt at the moment.
I think the biggest leap Gamefreak can make right now is making games with one region that is "Fully realized" in terms of scope and detail. Cities can actually look like cities and even towns will require less of a stretch to accept as a name for a given environment. In terms of exploration though, I am sure there will be obvious paths, invisible walls, and locked/missing doors everywhere.
It will be a "controlled" open world game at best in terms of map design. The locales can be meaty, but it won't be "you can climb that mountain" tier. Right now the only way they could make it feel legitimately open is figuring out a way to allow player to take on any gym at anytime, with level scaling/Pokemon availability based on Badge count, without breaking the game's difficulty.