I believe you if you had embedded artwork, it is still there. You can verify by Right-Clicking > Get Info > Artwork. If you see the artwork, it's there, just not displayed. I have all my artwork displayed now, all the time, on all my devices. It took me several hours, but I have zero issues now using the method I outlined above to restore the artwork. One note: a small % of albums needed to be done twice for the artwork to appear, but it did work on every one of my 1500+ albums.
Since the artwork is there, Apple will probably have a fix; just be patient. If not, my method should restore your library; just takes time. I believe this is just some sort of tagging issues. To be safe, I've disabled Automatic Artwork Updating...
The other issue some people are mentioning: extra time on some songs is a little different. I don't know how long most of my songs are, so I have no idea if some show more time, but I can confirm some of my songs 'replay' the last 10 seconds or so before going to the next song. Hopefully this will be addressed in an update as well.
Don't panic. I don't believe any embedded artwork has been stripped; it's just not being displayed. To be safe, backup your library now in case an update does strip it...