Ubuntu and other favours did this a while back
- Drop Adobe Flash as it will be EOL before end of next LTS
I believe we did have some discussion of this at the time, and either said leave it, or did not make a firm decision.
Have added a launchpad bug: https://bugs.launchpad.net/ubuntu/+source/ubuntu-restricted-addons/+bug/1751752
I think it is appropriate to re-visit this discussion before be go to beta.
Flash will remain in the archive and be installable should one wish.