very often musicbrainz starts to search for the file, but it never finishes; there is no message and maybe nothing happens. In these cases I can wait endlessly, so an internal timeout would be a good thing.
Further, these requests disable the musicbrainz-button (undtil I quit the dialog) but it should be enabled after klicking on the next/prev buttons on the metainfo dialog.

As mentioned in another thread you started - you'll probably get more of a developer response if you post these wishes on http://bugs.kde.org (after searching to see that noone else has already posted them). Feel free to add more info to other bugs if they already exist.