I'd say that having the game taking place just 20 years after OOT/MM would either mean we get a rather old Link (as old as nearly 40 or as young as nearly 30), and I don't really see that. And if we have a NEW Link that would mean that the Hero of Time would have died really young, and being reborn shortly thereafter. That's nothing that we see in the series, usually there's 100's of years between the games.
And the Sun falling down thing and things getting brighter got me thinking; if the world gets brighter would that mean the game gets brighter/whiter? I'd think that could cause some problems if things got too "white" with light, so you wouldn't be able to play with that much brightness.
Yes, elements of previous games has been used quite a few times (light/dark world) but having the sun fall down AND using masks (and possibly time travel?) would be recycling too many things in one game.
Anyways, that's my thoughts on why this is fake. Maybe I'm wrong though, but I hope I'm not; this isn't the Zelda game I want.