To sum it up, things missing:
1. Reverb
2. Two algorithms in Maximizer are not there.
3. Other dithering algos apart from MBIT+ are gone.
4. Imager misses controlls for phase, polarity and delay offset.
5. Gate/expander gone
6. Dynamics histogram view gone
7. Due to the change of GUI the scaling sliders for individual processes are gone and these were really useful.
What we got:
1. Nicer GUI
2. Dynamics EQ
3. Standalone app (which I don't really need)
Conclusion: it is an obvious downgrade from version 5, at least for users of Advanced.