in the next TES? The CoC is in Skyrim. I'm thinking Mora will reference him or we'll be able to see how he turns out.

The CoC is and is not in Skyrim. He/she is in the sense that he/she COULD have become Sheogorath. But there's no certainty. Nothing more than a few nods towards Oblivion's storylines, which any Daedric Prince could be very familiar with.

But yes. Perhaps Mora will mention the Dragonborn, most likely in a very small way.

It would make sense if Herma mora said something like "Even a dragonborn... cannot evade me... forever" if you chose a dialogue option that was againts serving him.

Actually, he mentioned almost everything that happened in the main quest and also in the major side quests, and said he was there for the whole thing.

The CoC isn't in Skyrim. Assuming we go with the theory that the CoC became Sheogorath, the CoC would have fully mantled Sheo by then.

Or at least that's the way I look at it. So having said that..

There will be a reference to the Last Dragonborn in the next game, as has always been the case, but probably nothing significant.

Of course he was. He had a doorway into his realm just down the Niben. The thing about 'canon' in TES lore is that no hero does everything. SOMEONE became Listener of the Dark Brotherhood, SOMEONE became head of the Fighter's Guild and SOMEONE became Sheogorath after stopping the Greymarch. It was not the same person - unless that's what you roleplayed.

It COULD be the Champion of Cyrodiil in Skyrim, but it could also not be.