> will ultimately replace menus in Unity applications
Why? Obviously, HUD and menus have different functions, and different use. GUI menus might be more appropriate for GUI applications, since you have your hand on the mouse already and you don't need to move it to the keyboard to type the command.
> fuzzy matching, and it can learn what you usually do so it can prioritise the things you use often.
Every time that I saw something like this in any application/OS (Android is a prime example), it was such an epic fail that it is almost beyond words.
1) I usually learn faster than a computer, so the way I see it is not computer "learning", but computer arbitrarily "changing" its behaviour. So, instead of memorizing "to call Jack, I have to press J and Down and Down", I have to always pay attention when the interface changes...
2) If there are some actions that I do much more commonly, then give me a way to access these actions more directly (interface buttons, scripting, keyboard shortcuts). But, in any case, my shortcuts will be almost always better than "automatic" ones, and also, mine won't change.
Fuzzy matching can be good, but I've yet to see a good implementation, and it, above all, has to be consistent! Not as in Android, where matching is "fuzzy" for calling, but exact for SMS...