I learned today that Apple overhauled iCloud Drive in Sierra, which led to a bit of a shock.
Do we know yet how we can disable the "Optimize My Mac" option in iCloud settings? (this should really be opt-in). Do we know if this will be added as a config profile option down the track?
Also do we know yet how to disable adding "Desktop and Documents" to iCloud Drive? Again, should be an opt-in thing.
I think they finally added granular control over the Desktop and Documents feature, so you shouldn't have to disable iCloud entirely to stop this in 10.12.4.