I’ve complained about the new Info windows in iTunes; they’re ugly and hard to read. But there’s a way to use the old-fashioned Info windows. It’s well hidden though.
Select one or more tracks, press the Option key, then right-click and choose Get Info. You’ll see this window, the one familiar to iTunes users for many years, in the colors of Yosemite:

I’m told this works on Windows if you press the Shift key, then choose the contextual menu.
So, if you hate the new tagging window, you can still use the old one. I’d have expected this to also work if you press Command-Option-I, but it doesn’t; it only seems to work when you hold the Option key and use the contextual menu.
It’s interesting that Apple has kept this in iTunes, even if it’s hidden. It suggests that maybe, just maybe, the new window is tentative, and there might be a return to the older window.
H/t to Doug Adams, who passed this on from Paul J.
Update: as a commenter says below, you can apply a keyboard shortcut to this. In System Preferences, go to Keyboard > Shortcuts > App Shortcuts, then click +. In the Applications menu, choose iTunes; for Menu Title, enter Get info; and for the Keyboard Shortcut, press Command-Option-I (or another shortcut, if you wish).

One extra key to press, but you can display the old Info window as before without even using the contextual menu.