Well it's been confirmed that there will be (at least a few) carriages in the game, but horses (as far as I'm aware) have never been confirmed, because they were worried they wouldn't be as good as those in Red Dead Redemption.
So does the inclusion of carriages mean horses are in?? If not, what on earth will be pulling them??
No, because one thing doesnt follow from the other. Morrowind had silt strides for travel, not for riding.
They were trying to get horses done right, and they wont do them if they dont feel adequate for the game. Todd said that already. The IGN interview confirms (because of him not answering about horses at all) they are still trying to do horses, but theres nothing definite.