Please, there is no need to become paranoiac.
As far as I know, iCloud is not supposed to synchronize the versions, only the main documents.
If you move the file xxx.pages from HD1 to HD2, it already loose its versions datas.
I don't use Dropbox but I assume that it behave the same.
In most of the threads about this feature, what was feared was that versions were shared thru the net which was clearly not wanted by the users.
I wish to add that I agree with your sentence to which I just add one word :
"Happily, this new saving paradigm is coming to all apps."
Yvan KOENIG (VALLAURIS, France) mardi 21 février 2012
iMac 21”5, i7, 2.8 GHz, 12 Gbytes, 1 Tbytes, mac OS X 10.6.8 and 10.7.3
My Box account is : http://www.box.com/s/00qnssoyeq2xvc22ra4k