struggling with it myself too, but not got around to compiling a coherent report on the subject. Matt's mentioned that they're working hard on it atm, which is hopeully a good thing.
I had the people tag showing in that window yesterday, and then, while typing in the search bar, MC kept interrupting my typing to ask me if I really wanted to apply the changes to the people field to these several thousand files!!!
So, no, atm, you're not the only one. I make two of us
I do know that I have a handful of image tags that I placed in the 'Display' category, and in 11.1, I'd use the panes for most tagging, and then, as I worked through my list, I do some stuff with those fields, handily available in the action window. While I've not tried yet, I don't see that this is going to be easy, if at all possible, with the new system.
Matt mentioned that the idea is that we 'zoom' into a tag, say people, fx, then work away applying people tags to our images. I think I'm going to find that a tough adjustment to make. I'm thinking, seriously? go through the whole list tagging people, then change the tag and go through the list again, then change the tag and go through the list again, etc. etc. Surely not?
On top of that, the AW won't expand. So despit the fact that tree is fully collapsed, the AW remains compact and crams all the [people] into a tiny space requiring a mega ammount of scrolling to find the correct tag.
I still can't change a files [media type]. I'm often struggling to discover a files [file name] whereas before, it was right there in at least two places (action window and tooltip)
I'll post more when I've played with it some more.