Oblivion had both first person horse riding and button controls only for steering. It just lacked mounted combat. There is absolutely no reason why first person riding and button controls only for steering wouldn't work in Skyrim.
like I said, you're still disregarding several elements that factor into Skyrim when trying to implement such a system that aren't
at all present in Mount & Blade. you seriously can't expect a game like Skyrim to be as competent as a game who's
primary focus is mounted combat.