The major problem with revising system as you described it is that is used in Anglo-Saxon countries and Scandinavia only AFAIK. This keeps it a sort of on a back burner at GS as there would not be an obvious benefit across the user's community. Do not get me wrong this is a long standing wish and I would love to have this implemented one day.
BTW there is an add-on solution for this done by Cadimage - Revision Manager
http://www.cadimagetools.com/tools.aspx?id=24 However I have not used that so I can't tell how effective it is but it seems to have all tools for clouding, transmittal records, revision and issue tracking.
Obvious problems when implementing it:
1. issuing already archived documents along with new revised documents in one transmittal record.. how and where to keep archived copies (file size etc...)
2. issuing non-AC items (specification, physical model, material samples and whatever) along with AC layouts
3. technology that would allow to see changes on drawings since the last issuing
4. all of this working in Teamwork
5. solving the transmittal record and revision history customisation. I saw probably 1 million different formats in my career.
Some comments:
There is no way I would allow AC itself to cloud changes... it could be very deceptive and dangerous. Clouding and cloud annotation must be kept as a manual process (AC would be helping just to identify changed areas).
Do not get carried away too much with Mac UI
AC has to fit onto both platforms.
::rk