I would love to see a new city or town in the game, even though this is a direct sequel, or maybe a route to get to Anville Town rather than using a train to get there, any suggestions?

I think a lot, if not all the cities and towns deserve an improvement. Many towns lacked interesting events within them, so such an update would add a flavor. Adding more cities to the same region is, as I believe, not necessary. The region would seem to be too crammed. However, adding another land (island) with more towns would be a good addition, I assume.

Since we're talking about a potential sequel, $10 says that we're probably looking at very few "old" cities/towns being kept, if at all. Which means, yes, "new areas" is going to get fulfilled by a long shot! Right? As long as CoroCoro didn't lie that time...

I don't think it's gonna be the same region. Remember how Looker said they found N somewhere during the completion of the quest in finding the 7 sages. Also the first time credits screen shows N flying away on his pokemon.

I think we're going elsewhere to conclude the story. They seem to be less interested in introducing new pokemon and more on expanding the story. I wouldn't exclude the possibility of a previous region, even Hoenn, and giving us the opportunity to catch Pokemon that had become unavailable since phasing out Gen 3, such as the regis.