I knew about the 'slide to counter turn' combo of keyboard and mouse but find that very cumbersome. I've pretty much gotten used to things now. One advantage Sky has over OB here is that in OB you could only look up to 90 degrees left or right while riding - even stopped. In Sky at least if you stop, you can look 360 degrees around you.
Heh, can't help with melee - either on foot or from the saddle. Buffy doesn't touch the stuff.
That said, Buffy's followers, when mounted, do fine with melee and are quite helpful in fact - thanks to CH. Even little Brelyna will draw her ebony dagger and rail away on foes from the saddle, giving Buffy and Superian a bit of breathing room to bring that mighty mystic bow to bear.