I have just read all of this thread and man is it an annoying read. Tons of people complaining, a brave few trying to help, but for the most part actual answers are ignored and rather complaints (a few of them actually unsubstantiated) are being repeated over and over again. I thought people on discussions.apple.com were actually looking for answers. Unfortunately quite a few only seem to come here to vent.
Anyways:
If all the same functionality is still there, riddle me this...
In prior versions, after inserting a CD I was able to select tracks on the CD and drag them to a playlist in the sidebar so that those tracks would be imported and added to that playlist. How do I go about accomplishing the same thing in iTunes 12?
Let me guess, you haven't bothered to actually try it? Because if you had, it would have been blatantly obvious! (btw: Sorry, no offense.)

It is actually pretty easy, just select the tracks from the CD you want to import, start moving them and voilà, the sidebar (magically) appears. They actually improved the set-up of this interface, because in this version of the sidebar only the "manual selection" playlists appear, "intelligent playlist" are not shown, because you can't drag files onto them anyways. I guess this is also the reason, why the sidebar is not permanently visible, when looking at a CD, this sidebar is generated "on-the-fly" when you start dragging tracks and only shows playlists you can actually successfully drag to.