This works for me on Ubuntu 20.10 and Windows 10.
For some reason, the command history is empty when I start with that option.
Being able to enter any characters on my keyboard without the fear of crashing the command window (on Windows) is a huge improvement imho.
I wouldn’t even mind if input and output were separated (like they currently are with the experimental terminal widget) if implementing a combined input/output widget turns out to be difficult.
I’d find it more convenient if the input line was below the output text box though.
It would also be nice if the font was used that was set for the command widget in the preferences.
The only major drawback (and possibly the only point why I wouldn’t start using it on a daily basis just now) is this point you mentioned:
When that point is resolved, we could set the new terminal widget as the default imho (at least on Windows).
Would it be possible to have an option in the preferences to select with which terminal widget the GUI should start by default?
Support for readline in the input line would also be nice to have.