The whole Delta Episode clears some things.

Sootopolitan Wallace states for the battle against Wallace in the post game. There is no indication of Juan being the new gym leader, but i can see it happening.
We have actual proofs that there were alot of missing artwork in the demo data, such as Zinnia's one. More to come, like Battle Frontier Brains and Juan.
Also data is incomplete in terms of learnt moves and such, as we can see by looking at Blaziken on the official site.
There will be no cutscene with Rayquaza vs. Groudon and Kyogre, but we will get a space cutscene instead. This is only a speculation though.
It seems, that Hoenn is tied more to Kalos than Johto to Sinnoh.
At this point Delta Emerald is 0%, since the plot of ORAS is heavily dedicated to Rayquaza.
No sign of Hoopa indicates, that it will be event legendary mon like Diancie. Hoopa-H in Z/X2/Y2?
Leaders of villainous teams are nowhere to be found.
There are more mega evolutions to be found in the game, but it is obvious.
Reggies are to be found in caves, braille is involved.
Still no info about Battle Resort and Battle Frontier. I think Battle Resort is a reskinned Battle Maison from XY, and Battle Frontier is slightly changed.

Neat, i am even more hyped, post game seems like a lot of fun.Ignore shitposters