I was so excited by the prospect of a new version that I stayed up till the middle of the night to install it 😁. Now I too would say that iTunes 12.3.2 has solved the serious problems that the previous version had. The first start after the update was still slow but later starts were much quicker (down to under 2 minutes now). I can use the program again. Yippee!
But you win some, you lose some - a problem has arisen which wasn't there in previous versions. When I define new Playlists within a Playlist Folder (which is how my iTunes Library is structured), the new Playlists are appended after the last existing Playlist, e.g. as has happened to the last 7 Playlists here...
In previous versions the Playlists where sorted into alphabetical order "on the run". With the current version the Playlists do appear in the expected place alphabetically when the program is restarted, so I don't see this as a problem worthy of its own thread. I'll report it via Feedback and hope it will be corrected in a future version.