I have this exact same issue. The thing which "bites" for me is that I have a few MacBook Pro's which I need to keep on Mavericks because of a few applications which I use for the mainstay of my work. My iMac, however, is on Yosemite.
I use all systems in conjunction with one-another during my work day, it has to be this way. Some modeling stations, some rendering stations, and all tend to be my note-taking & document stations as I work on them, etc...
Now, I can't simply open documents, cross-system, even though they're all Apple OS's, sunless I go to my prefs & tick/un-tick that box, which will then invalidate ALL of my MacBooks from being able to access the files which I use on my iCloud.
What gives... Apple? Did my prediction come true, that the day Jobs died, the Apple started to rot?
Simple compatibility and you can't even do THAT for us? And worse, it's STILL a lingering issue from 2013?
UGH!
#ms-apple