Alas, I fear we are talking to ourselves here. I think we'd have
to post something to debian-knoppix to get any attention.
Speaking only for myself, I think it is good to discuss and test out the ideas as far as possible before we eventually suggest something to Klaus K. If we have aggred on some new features, and can produce "proofs of concept", it will also be much harder for him to reject it, too.

Your dropping of persistent image changes is easily implemented with the nowear option and a question about saving to store on shutdown.

The compressed backup can be produced with another alternative, Create compressed. Maybe wh could then have 3 shutdown options + default (save&exit).

<CR> : Save image and exit
N : No saving of image. (Option not available without nowear cheat code.)
C : Create compressed backup, e.g. knoppix-data.img.gz
M : Maintenance mode. /UNIONFS is unmounted etc

Doing things this way, we could also have safer unmountings of file systems.