dont know about that... the user group access system has been totally improved and the new templating system offers loads more opportunities that aren't possible in 1.5
Most sites don't need the ACL that 1.5 has now. And for sites that need it, there two well established extensions out there that have already worked out the bugs,
Nested categories...OK, but for most small business sites are they really needed? Not so much.
Templating? Oh yeah you mean...where you can assign page suffixes and different color schemes/views from the same same template to menu items?
One word....Gantry!
Don't get me wrong I'm looking forward to the upgrade, but I was one of the people who started building a site in 1.5 when it was RC and it was very time consuming. So I guess I'm just over it.