If one edits a document, then chooses Save As, then BOTH the
edited original document and the copy are saved, thus not only
saving a new copy, but silently saving the original with the same
changes, thus overwriting the original.
If you notice this auto-whack, you can “Revert To” the older
version (manually), but if you don’t notice, then at some later
date you’ll be in for a confusing surprise. And maybe an
OMG-what-happened (consider a customer invoice that was
With nearly all of these changes in 10.7 and 10.8 regarding documents and saving, it’s easy to see the tradeoffs involved. Maybe you prefer the old way, but you can see how other users (especially new Mac users) might benefit from the new way. But with this change to Save As, I can’t see how anyone benefits.