1. Deafened NPCs
Clearly an oversight by the developers. It should be patched out, if possible.
2. The Fetch Trick
It should be patched out. It’s fun and makes target manipulation simple, but it’s unintuitive and counterproductive. You mentioned the ubiquity of this “glitch,” and I think it ultimately falls to “Dominant Strategy.” When one method is easier than another, why bother doing anything else?
3. Blind Panicked NPCs (report to guard version)
This is simply a limitation of the AI. I feel it should be patched out.
4. Blind Panicked NPCs (mass panic version)
This makes sense to me. People have priorities, and when a bomb goes off (or something), I can guarantee that my attention will be shifted to myself and the few around me.
5. Hidden Crouch During Animations
Obviously an oversight; should be patched out to make the game more intuitive.
6. The Amnesia Trick
Another oversight. While extremely convenient, it should once again be patched out.
7. Fast Throw
I actually don’t have a problem with this. While I don’t understand why it happens and it looks extremely silly doing it, you could at least argue that it takes some form of skill (albeit, a possibly benign form of skill). Essentially, with the proper timing, you can perform a “fast throw.” While unintended, I think it should be fleshed out into a feature.