There are also some other goodies in there as well, like the fact that Windows file sharing will now only work on local subnets by default (though an admin could change this).

I know that they are making these changes to try and tighten up security, but I don't think it will work. The end result of these restrictions is that more code will get run as admin.

When developers are faced with "fixing" their code to work will the restrictions or just to run it as admin I'm afraid I know which course many will take.

The changes to IE to provide add-on management look good though.

There are a few changes to IE's window.open() etc al that will break lots of rich UI Intranet apps that I have worked on in the past. Yet again there are changes to the MIME type handling when download files output by dynamic ASP/PHP/CGI/etc, which will further complicate an already frought area when dealing with multiple version of IE and their integation with different versions of Word/Excel/Powerpoint.