I have read so many requests here that have not even gotten a response from Autodsk about all of the BUGS in 2013 and the Developers are silent on almost all of the discussions. UNDO takes me back through the 15 Zooms I used before the last command??? It never did that before.. and only does it 1/2 the time? How can you screw up UNDO and not talk about it or fix even here? It's not like 2013 came out yesterday either. Unbelievable. Folks Autodesk will not get off their focus on the next full of Bugs release if you don't call them out on the Carpet and demand quality software. Read through here at the multiple requests of users for an answer to the UNDO ZOOM problem. This should be called the Lack of Support area.
This is actually something that the AutoCAD team is looking into at the moment. I would suggest you leave your feedback on this function by following this link: http://usa.autodesk.com/adsk/servlet/index?siteID=
The feature of UNDO combining zooms is actually part of your options, see attached image. While there are definately other issues, maybe this little one will help.
This setting makes no difference on my system. I stillget reports I have done a trillion UNDOs.
You don't really need feedback for this one, just make it work like it did in 2012.