Mounts are certainly NOT a waste of time if they perform properly a la Red Dead or even Assassin's Creed.
I never use them in Oblivion. Out of all the horribly done parts of Oblivion, horses are one of the worst. They don't move enough faster than the player for it to be super appealing, and they're just clunky and frustrating. Without mounted combat they make wilderness areas really frustrating as well. Taking damage as you get off your horse is annoying, especially when being mounted should be, in most situations, a combat ADVANTAGE, and when the game bugs, it's even more frustrating. I tried to get off my horse once but, when it went to put me off, there was a rock next to the horse, and apparently it wasn't proper alignment for the game to put me off, so I sat there unable to do ANYTHING, and the game finally put me through the dismount animation and I was able to start fighting when I was almost dead entirely.
That being said, I'm a big proponent of allowing the role playing aspects to flourish amongst the people who want them. I would very much like horses to be in Skyrim, even if they're the same horses that were in Oblivion. Just because to some people it seems to be a big thing. On that note, I'd definitely prefer horses in the game to be much improved over Oblivion. Making them control more realistically (not going from start to go and back so clunky, not turning so clunky, etc...) and including a well done mounted combat system would make horses offer a gameplay reason for use. Also seeing the horses actually significantly faster than our player character (and not by slowing down the player character but by speeding up the horse), would offer even more of a gameplay reason for them to be there. And the final request I'd have for a horse system would be the ability to have a horse inventory with a certain encumbrance (depending on the type of horse) that you can dump loot into especially for weaker characters that can't continuously loot or mass loot and be able to make it back to civilization.
And finally, I'm VERY glad to hear you can't ride the dragons. That would be ridiculous. They're enemies in every sense of the word, as mentioned in the podcast. They're also intelligent beings from what I can tell that probably wouldn't even allow it if they were friendly (which I suppose a few might be, as I remember one of the dragon voice powers being something about summoning the aid of a dragon). While I'm definitely all for role play freedom and doing all sorts of things even when those things might not appeal to me, things that go against the lore are a no. If there are concessions there, then what's to stop people from asking to ride liches and ghosts and daedroths? If it's not something that can be done in the TES universe, leave it out. The game needs to allow complete freedom, but only where it doesn't destabilize the game and the TES universe's rules.