Haven't read the posts in the thread aside from the OP, so someone probably replied something similar, but here's my opinion:
Shadow of the Colossus is a game that has aged terribly. The controls are awkward, visuals are inconsistent and that heavy atmosphere of a lone warrior against a giant isn't really recaptured on the HD version, if it ever had it on the original. I never had the chance to play the game back when it released, so this probably influences my opinion, but still. It's a decent game, one with a specific and focused task but that unfortunately falls into monotony and emptiness. The landscape, as much as I tried to love it, was extremely barren. The gameplay isn't really that fun. Once you figure out the Colossi weakness, which admitely can be interesting, it fades into an exercise of monotony.
On the other hand, I think Ico is superb, friendly AI issues aside. But then again, I had the chance to play Ico back when it first released, so probably nostalgia is a factor to have in consideration.