Cinnamon 3.0.0 has been released (but not yet announced at the time this post is published) and sources are now available in their github repository. I took this chance to build the new Cinnamon 3.0.0 on top of latest Slackware Current update on my desktop and so far, i haven't found major issue with this build.
Tonight, i'm planning to build Cinnamon 3.0.0 on top of clean Slackware Current installation from a clean VM and i will publish the unofficial packages for public testing. Hopefully it can be integrated in the next Slackware Live ISO release by Eric Hameleers.
If you are interested to try, you can always build them from source via GITHUB (development branch).