A different background image on the host and different theme to differentiate between Whonix host and Whonix VMs is a good idea. Not convinced yet that Whisker Menu has to be gone on the host though.
Not sure. First the host operating system needs to become reality before implementing amnesia.
A lot discussion on amnesia happened since this very post:
Whonix live mode / amnesia / amnesic / non-persistent / anti-forensics - #121 by Patrick
As per above analysis appears to be done for now and development tasks are created.