My big beef with V4 was that I could no longer use acoustic mirror plugins on tracks or busses, and it (Chicago Theatre) was my favorite for snare reverbs.

I found that it is the ASIO Drivers that are causing the problem, and that when I go to mix my projects...and am no longer needing the ASIO features for tracking, simply go to Audio Devices and change to sound mapper.
Acoustic mirror will now work for you.

I haven't checked to see what WON'T work...but A.M. sure does.
Have fun!
Pete