-It will be revealed that Ganon utilized a sacrificed past incarnation of Princess Zelda to regain his Gerudo form.
-Time travel will be involved, and it will be revealed that BotW Link IS the hero from 10,000 years ago.
-There will be eight dungeons, more than the five(six if you include DLC) that we got in BotW.
-The Master Sword will once again be put to rest at the end of TotK like most other Zelda games it's in aside from BotW.
-The ''tears'' will have something to do with either the Sheikah or the Zonai.
-The end of the game will mark the end of the Calamity Era, but not the status quo; Ganon was already killed off in the AT and the CT(the one in FSA is a different guy with the same name, not THE Ganon who is the main overarching antagonist of the series), and Nintendo would be fools to kill him off for good at the end of TotK, especially since the DT is all about Ganon's constant revivals as the eternal scourge of Hyrule; he'll probably die again(although he could always be sealed), but not permanently. Like I said above, I can see the MS being returned to it's resting place for a new hero in a future era. Maybe TotK will be the last DT game for a while with Nintendo taking a break from it for some years or not, but either way Nintendo will move on from the BotW/TotK era.
-The Triforce will play a bigger role and will be mentioned by name.
-There will be a visible durability meter to see when weapons are getting close to breaking beyond the message you get when you're only a measly three hits away(one can hope, atleast; I'm fine with durability as presented in BotW, but some way to see how much you can use a weapon before breaking would've been nice).