I wouldn't say it's the "most disappointing", partially because that implies the others have been disappointing but also because I had realistic expectations for what is a filler title. I wasn't expecting an overhaul as significant as the N64 remasters received, and Twilight Princess was never as aesthetically pleasing as Wind Waker. Short of a major graphics overhaul (which would massively increase development expense and effectively rule out a remaster happening), Twilight Princess was never going to look beautiful in comparison to WW:HD. As it is, I think the bump up in resolution and the higher quality textures look decent, though sadly the geometry has aged poorly. The original TP aged far, far worse than the original Wind Waker did.
As for the amiibo extras, yes, the implementation sucks, and the Wolf Link cave isn't something I'm interested in. I'd also point out there's absolutely no indication Hero Mode is locked behind amiibo, which is what the OP implies, but is instead, as with Wind Waker HD, available from the beginning, which is something I welcome.