[Exxy]

I'm sorry, but this sounds like a pipe dream. The work required to see this through would take years to even decently realize, between mapping, programming, designing, etc. with the one programmer + few artist/mapping volunteers we currently have. Especially when a large portion of the 'advantages' can be replicated through other systems, which are much, MUCH quicker to implement.

I suppose you could take a page from how the first generation Pokemon games were developed in mind of a conversion of this magnitude. A lot of times, what you saw on the screen at the borders of areas was all of the mapping there was. The best way I can think of relating it would be to take a square and then hollow it out. Now, you're only allowed to explore/walk along the edge that's left over. There's still the illusion of the square, and content can be added as time progresses. It also wouldn't kill memory (I think). Although, I suppose the major backfire from this idea is you'd still be limiting off to one continent (possibly) and quest locations would have to be moved around (granted it is possible, unsure if plausible, to do - the guy who gives the sword quest in Oniga could become a tourist NPC in Tannis for example).

This'd probably be a more middle ground approach. Granted you'd have to be sure to include things like a lawless section to replace the actual Law's End in Oniga and other things (like adding churches where applicable and other small flavors to take into account so we can still keep that diversity from key locations in the Overworld if at all possible).