I came to this thread to say that Termina's story is basically told and that there is no need to ever return, but when I thought for it a bit in thinking of what to post I changed my mind. After all, you could make the argument that in Ocarina of Time, for example, Hyrule's story is already told - but there are always fresh (or not so fresh...) conflicts brewing. So instead, I will separate my thoughts into two questions:
1. Will Termina return?
I agree with those above who have said that Termina is a one-off world. I think that Termina has such a powerful mystique (Is it a parallel dimension generated by Link's mind? Is it an actual place? Is Tingle a Satanic construct? Inquiring minds want to know...) and the game Majora's Mask has a reputation as an oddball that I think the developers will leave its legacy untouched (except, perhaps, for an HD remake?).
2. Could Termina return?
Certainly. There is no limit to imaginative storytelling. Any number of things could have happened to Termina in Link's absence, both before and after the events of the game. Just because there was a three-day cycle in Majora's Mask doesn't mean that there has to be a similar mechanic in another game. Plus, the map can be expanded and shifted just as Hyrule's has been countless times. Majora's Mask lays a considerable amount of potential backstory or future plot for every region of the map:
Swamp
Past: How did the Dekus come to live in a palace? There could be a potential bloody history (well okay... I'm not sure that Deku Scrubs have blood at all) in terms of political coups and whatnot that led to the Majora's Mask era political situation.
Future: Do relations between Dekus, monkeys, and humans change? How does the Deku Princess fare as a ruler?
Mountains
Past: What heroic deeds did Darmani do? Presumably, there were outside threats to Goron Village over time.
Future: Maybe Mountain village expands into more of an actual settlement instead of one house. Do the Gorons and Humans come into conflict?
Bay
Past: How did the Gerudo Pirates end up there? With their proximity to the Zoras, there has surely been a lot of historical tension.
Future: At the end of the game, there is no reason for the Zora and Gerudos to have made up. They would continue to have conflict, I imagine.
Canyon
Past: What happened with the whole Ikana war that turned everyone into undead? How did Garos come about? The Sharp/Flat betrayal storyline could be significant as well.
Future: Does Pamela's father investigate the strange properties of the region and make any discoveries? With the return of water, does the region expand in population or become greener?
Whether or not you agree that there should be a return to Termina, I personally believe that there is plenty there that could be developed further. Imagine, for example, that there would be a side-game added to whatever the WiiU game will be (presumably in Hyrule) that takes place in Termina. That has some potential, in my view.