I think the game is amazing, and I'm having a lot of fun with it. As mentioned, there are some pretty bad bugs, but those will be fixed here soon. It's been so long since we've had a good game like this that I'm absolutely thrilled to be playing it.
Hm. I already sneak around a lot as is, but it sounds like I should just be sneaking everywhere so I don't miss anything.
I do think finding hidden things should probably be perception-based (or stealth-based) rather than mechanic-based... but eh. That's a really minor nitpick.
One of the loading tips definitely says that items like Grappling Hooks get used up during interactions. Though I haven't paid enough attention to see if they do actually get consumed or not (actually I'm not sure I've ever needed to use them since a lot of them can be worked around with a high Athletics skill, which I have).