I have been able to continue using the Zune Client, which does work on Windows 8, to manage my music on Windows 8. Here's how:
1) Download the Desktop Sync Client Beta (NOT the Metro Windows Phone App from the store)
2) Install and launch the WIN 8 Desktop Sync Client and use the Windows Libraries management option. Once initial setup is done, if you want to Sync All, use that option and sync to phone. DONE. If you want to be selective...continue.
3) Organize your playlists in the Zune client.
4) Once organized, launch the new sync client again and opt for syncing by playlist. Choose the playlist(s) you want, and Sync.
Not ideal, but it works. Haven't tried it with Podcasts.