I like your observations, and they make sense, but I disagree (and hope I am right)
Agreements:
It will definitely come at the end of a timeline. After making a big deal about 25 years of Zelda and wrapping everything up with an official timeline and origin story in Skyward Sword, and then going back to tradition with A Link Between Worlds, looking forward is the next logical step. Also, you're right that after Skyward Sword being an origin story from the beginning, Link Between Worlds being a Link to the Past love letter and Wind Waker HD being a remake, something new is also a logical expectation.
Rebuttals:
I dont buy the whole "the map looks different now" thing because I dont think they are really rigid on the maps being similar (outside Twilight Princess of course, which was pretty much Ocarina of Time 2, I hear), only that the landmarks are similar. I knew Minish Cap came before the other games because the places were unfamiliar to the rest of the series, but not because of the layout, for example.
Link to the Past, Oracle of Seasons/Ages and Link's Awakening have the same link, and so do Zelda 1 and Zelda 2, So there's only 3 Link's in that timeline. Seeing that the 3 Links in the Child Timeline are Majora's Mask, Twilight Princess and Four Swords Adventures, I dont think breaking tradition with how he looks in a timeline is much of an issue.
The VERY LAST game in the zelda series was in the downfall timeline, AND it has the most games in it by far, even if it still has the same number of Links. The other timelines are in DESPERATE need of new content, I think. Especially the adult timeline, which could use a non-toon Link.
Finally, the absolute best place to rethink Zelda conventions would obviously be after Spirit Tracks. All new Hyrule, no Ganon, no Vaati, no Dark Link, nothing familiar in the slightest, outside of Link, Zelda and whatever races and people immigrated with Link and Tetra. They can do anything they want there. In the Downfall Timeline, all the bad guys still have a MAJOR hard-on for reviving Ganon anyways.
