The fifteen Gods of Theros, making up much of the mythic rarity of this block, are one of the main attractions of the set and the planes. The prospect of a board-changing enchantment that changes into a finisher-quality indestructible creature when you're committed enough to its colors in your permanents is always a cool prospect. But although the God creature type is certainly popular enough to return, as is the keyword devotion, they won't be associated in the future, according to Mark Rosewater, for variety's sake.
When numerological asked Rosewater on his Tumblr blog, "Do you think you would use Devotion to represent Gods in another mythology-inspired plane? How about enchantments as their 'divine power' (though not necessarily Bestow)? I would hope so, it is elegant design," Rosewater answered:
If we do gods again, we would have to figure out what does every god do and what did the Theros gods do that was unique to them.
This oblique answer seems to indicate that the general themes of the Theros Gods might remain intact (having to maintain certain conditions to keep their "favor" and have them active, and making them very difficult to kill, are certainly two big things to do again, since they fit so well with the very concept of a God), but the mechanics of, say, Egyptian-themed Gods would be quite different.
Since an Egypt-like block would probably have a graveyard theme, for example, those Gods would probably check for whether a certain number of cards were put into graveyards each turn in order to have their abilities function, and Norse-like ones might be combat-themed, checking for attacking and blocking creatures.
What other kinds of God creatures would you like to see in Magic's future? Let me know in the comments.