I instead actually enjoy horse riding. The only thing that bothers me a little are small obstacles that completely stop Roach even when at full speed (when imo he should be able to jump over them automatically, especially if galloping; horses aren't stupid, they avoid and jump over obstacles by themselves. they don't need constant input from a jockey to do it), but apart this I like strolling around. Maybe with a controller is different but with K+M Roach is easy to control and enjoy.
Of the games I played that have horse riding as a mechanic W3 is one of the better at it. Skyrim completely sucks, in Inquisition the horse is practically useless and after trying it once I saw no point whatsoever on it being there, Mount and Blade is not badly done but the context is too different to make a proper comparison, Red Dead Redemption is very good and the only one of these that's better than W3.
So, all in all, I find W3 horse riding well done. Red Dead Redemption is better but given the context of that game horse riding is a primary factor, much more so than in W3, so it is obvious that the devs dedicated a lot of focus on having the mechanic work as good as possible. Apart some little awkwardness here and there (that I'm sure CDPR will adjust by and by) W3 is not so much inferior to RDR as far as horse riding goes; the feeling is there so it's only a matter of making some slight changes.