Well horses were made quite good actually IMO. For the animation and visual part. As for usefulness,as I said - remove fast travel,you'll start liking horses really fast.
Hmm... In Oblivion I've used neither horses nor fast travel ... Neither an awkward mount nor unaccounted for travel appeal. Fortunately, walking is good for you. (Or however the folks in Pelagiad used to put it.)
There is a HORSE in the trailer. You can clearly see it in http://i.imgur.com/MKm9O.jpg screen capture. That pretty much confirms horses, no?
It confirms their presence, but not that we can ride them. Coco-nuts and a bard might have to do for heroes in Skyrim. Maybe future screenshots or videos will tell.