This is a good list.
The biggest issue is the virtual keyboard. Years ago we choose the 3rd-party Maliit keyboard, but it hasn’t worked out super well, and we’re currently in the process of developing a replacement: Plasma / Plasma Keyboard · GitLab.
Once we have a reliable virtual keyboard, it becomes feasible to develop the rest of the UI around it and fix relevant bugs. Most of the items on your list should be fairly feasible to fix. The hardest-looking one is the open/save dialog issues.
Making it possible to easily use and toggle without a touch device is important too, for improved testing opportunities.