The "legacy" metadata editors, for which there was a "back door" in iTunes 12.0, have gone from 12.1. However, the revised editors in 12.1 provide access to (almost) all the metadata elements that were available in iTunes 11, albeit in a different layout and with some additional constraints based on media kind. Some users have / will have an issue with the statement that "Get Info has been completely redesigned in iTunes 12 to focus your attention only on what’s necessary for the selected item" since that removes some metadata elements that people may have been using in creative ways. iTunes 12.1 basically gives you access to the fields that Apple think are necessary ... 😟. Some of the things that have been excluded by this rule:
- track and disc number fields for video media kinds
- show and episode fields for music
- description tab for audiobooks made up of more than one file
Obviously the first two examples can be regarded as "overloading" the metadata elements - i.e., using them in ways that the designers didn't intend - but given that some users do find valid cases for this it's a shame that they've been deprecated in the new UI. There are couple of workarounds:
- in songs view (or any of the other columnar views), you can still select any fields to display, independent of media kind, and these can be edited (though only one at a time) by double-clicking in the relevant "cell"
- you can (temporarily) change the media kind of an item (or group of items) to get access to metadata elements that would otherwise be inaccessible.
It may be worth submitting an issue via https://www.apple.com/feedback/itunesapp.html - I can't see it as a huge development task to have a user preference to switch between "show all fields" and "filter fields based on media kind".
One other oddity/irritation is that some of the tabs don't, by default, show all the available fields - you need to scroll up/down to access them or to expand the window by dragging on one of its corners. Fortunately, the latter seems to be persistent - once you've done this to make all the fields visible the editor will open at the same (larger) size when opened again.