So Fast Travel does not ruin exploration because in an entirely separate game that had it you personally didn't use it? Riiiigghhht.
Besides that terrible argument I agree. If the countryside wasn't bland and repetitive than it would be worth exploring. Seeing how it is supposed to be this time we don't have a lot to worry about. If we have mounts and they look better and work better than there is no problem.
My comparison to a game that has incredibly similar travel systems to Oblivion and is also a huge open world sandbox game is a terrible argument for why fast travel doesn't ruin exploration? Congratulations on not thinking things out and going out of your way to be a jerk.
Example, your options for travel in both games are: Walk, ride a horse, fast travel. Oh and let's not forget how Todd Howard himself used Red Dead Redemption as a example of how they could better do horses.
In response to if mounts would be in the game: (Game Informer show)
[..] "There were things with the Oblivion horses. We liked having them. They weren't the greatest implementation of horses. And now you see things come out like Red Dead. There are more horses in games, and we feel like just the basic implementation we did in Oblivion isn't going to be good enough." - Todd Howard.
So yeah, my argument is invalid because Bethesda never looks to other games for what people like and how they can improve things. OH right... They have team meetings in their demo room at their office where they play the games in question and discuss just that.