I'm feeling super low on spoons today, but something I looked at this morning was possible responsive solutions for Installer & Initial Setup. This includes a fix for the window being too big in VirtualBox in legacy boot mode:
https://github.com/elementary/installer/pull/661
https://github.com/elementary/initial-setup/pull/152
Has some issues to work out, but it's fun to play with
A lot less interesting, but still important imo is revisiting some dialog copy to try to make it more human-readable, avoiding the word "user" and other jargon etc. Explaining consequences of the error and using more descriptive iconography.