After writing a fairly long reply to a mc11 thread just now I have some suggestions for mc12:
1. Add a function or option to the replacement text utility to automatically strip out spaces and other non-alpha/numeric characters and add ";'s" between each extracted whole word. This would make forming keywords from input text so much easier. E.g. If you replaced text "c:\insert\ridiculous\long\path\here" it would output "c;insert;ridulous;long;path;here" THAT WOULD ROCK.
2. Even better, add a new string transform to the calculated fields syntax to allow a user to generate the same type of effect as item 1. E.g. FormatKeywords([Filepath]&[Filename]) would populate a calculated field with all generated separated tags from both the filepath and filename fields input text.
3. Add a tag cloud view much like
http://www.flickr.com or
http://del.icio.us does so that any field-type that uses multiple values in MC could be visually represented, linked, and compared as to how many files there are. E.g. if you have tons of techno mp3s and some rock mp3s, the keywords tag cloud would show the keyword "techno" text bigger than "rock." Further, when you click on a tag in the cloud.. it would then automatically add "+'s" next to each subsequent relevant tag so you can easily refine your search to get specifically what you want. E.g. if you click on "rock"... it would then display a cloud with keywords "+ heavy", "+ soft", "+ lyrics", etc. so you can tell MC to search "rock" and some other related tag. Not sure if this view could be added to theatre view but I know THIS WOULD ALSO ROCK!
4. Old one, but I still wish MC could import and use Winamp Input plugins so that it could play exotic file formats such as tracker formats. Then, I could finally say proudly that I use one player to play all of my music. It's just a pain to use two or more different players and switch between them. However, I also realize that this request opens up a whole new can of worms for the developers to deal with. MC's tagging abilities are too darn useful and versatile not to keep asking. Oh well.