Also, sometimes the "bloomy" sky in SotC felt more like a bug, because of how it would go back and forth unnaturally, depending on where you were looking, so i don't mind that they fixed that, too.
Last Guardian also fixed this, so it was likely a tech limitation of having to fake HDR.
Speaking on the "fake HDR", SotC indeed gets its unique look because Team ICO hacked together a really complicated way of attempting HDR on PS2, and it will probably be near impossible to replicate accurately. Even the PS3 remaster doesn't quite nail it at times. But the strange-looking skies and lighting works for the game since it's supposed to be a cursed land, where time does not pass normally. It looks subtly otherworldly.