I was just reading the book "Mysterious Akavir. Information about the continent Akavir" which can be found in both Oblivion and Morrowind. This passage in particular tells an interesting story about the Dragon's extinction and possible return. I'm not saying that this will be the lore Skyrim Dragons are based on, but it's an interesting read. If you haven't read the book you should, but check it out the excerpt here:

"Ka Po' Tun [in the continent of Akavir] is the "Tiger-Dragon's Empire". The cat-folk here are ruled by the divine Tosh Raka, the Tiger-Dragon. They are now a very great empire, stronger than Tsaesci (though not at sea). After the Serpent-Folk ate all the Men, they tried to eat all the Dragons. They managed to enslave the Red Dragons, but the black ones had fled to (then) Po Tun. A great war was raged, which left both the cats and the snakes weak, and the Dragons all dead. Since that time the cat-folk have tried to become the Dragons. Tosh Raka is the first to succeed. He is the largest Dragon in the world, orange and black, and he has very many new ideas.
"First," Tosh Raka says, "is that we kill all the vampire snakes." Then the Tiger-Dragon Emperor wants to invade Tamriel." -book 'Mysterious Akavir'

Assuming Bethesda even remembers this book was in their games, I still doubt this'll be relevant. The Dragons shown so far seem very very different to the Akaviri variety, and are apparently heralds to Alduin (Akatosh) the World-Eater's arrival.

Orange, red, black dragons. I hope we see all of those!

That may be true, but maybe these tiger dragons will make an appearance in Skyrim? Just not be the main dragons. Maybe they join the forces of Alduin and Tosh Raka is some sort of boss.

Indeed I'm pretty sure that the dragons in Skyrim are not from Akavir, but rather Jill...aedra dragons. Guess we'll find out

Yeah, I doubt they'll even consider this lore in Skyrim. It's still interesting to see dragons mentioned in the earlier games though.

Apparently the Tsaesci are actually man, yet that book percieves them as serpent people.

Akaviri Dragons are not the same Dragons that are in Skyrim

Tsaesci are immortal. vampire. snakemen. The skeletons in Pale Pass were a gameplay limitation.

man I want to see at least a few new creatures and [censored]. asin lore creatures.

Yet if it were a Gameplay limitation, why make it so that the Scout writes down on how he broke his legs? It seems clear to me that they were intended to be Human, even if the reason they were so in the start was due to being unable to create a new snake-like mesh in time.

It's either yet another retcon, or perhaps fitting into the theory that the races of man DO still exist on Akavir, as a slave race to the Tsaeci ('Eaten' thus meaning 'Assamilated')

Though this isn't the thread for this.

Mike Kirkbride, the man who created the Teseci confirmed it was a gameplay limitation and that they are indeed what the lore says they are. No need to debate or speculate, the dev who made them has closed that chapter on Akivir.

edit: as for the journal entry perhapse the teseci took slaves while invading Tamriel, but I'm quite sure mk said that they litterally ate the men of Akivir.