I actually found the horse riding fine - it actually does provide a lot of steer assist when you're going over bridges, through forest, ravines etc. There were times when the game decided I couldn't go into full gallop which was annoying but not that big a deal.
And I'm not against difficult games. Probably my favourite game of all time is FTL & I've beat than on hard with multiple ships. But the difficulty I enjoy is one which challenges your decision-making, problem-solving, strategy and even your coordination (a la Spiderman). The difficulty I don't like is one which stems from trying to overcome flawed or sluggish controls or a bad camera.
The fact that it took me multiple attempts at the final boss actually detracted from the experience for me as when I'm scaling him for the umpteenth time after falling off because of imprecise jumping or excessive thrashing I'm thinking how much I want it to be over rather than marvelling at the awesome scale and design - which is what I should be doing. It's not about being overpowered - it's about being comfortably in control of intuitive controls.
I don't want to sound overly negative though - I guess the complaining comes from a place of frustration, as not many games hit the highs of SOTC, but then it seems to needlessly trip itself up with some relatively basic issues. It's only because I enjoyed some parts so much that I care enough to complain - if that makes sense...
I had the same frustration while playing the remaster. That final boss requires some odd timing. As far as I remember you can stab him somewhere so he holds still and it becomes quite easy. Or maybe it was shoot his other hand with an arrow. There is a way to make it a lot more easy.
I also had that frustration at the huge boss where you have to climb up the castle walls every time. There is also a 'shortcut' there yet like Dark Souls, you have to stumble upon it. If I had a better memory I would play it again. Ico has a frustrating part as well, where you have to time a ball launch or something. And TLG simply has a bug where Trico stops responding if you do things in the wrong order :/ No game is perfect.
Hence it's nice to have all that down time in between the bosses :)