This can be done with an utility which can edit and load custom LUT.
I have tried Lutcurve utility, there is a trial version for testing.
You can edit the brightness curve to dim the white color. (see the "highlights" tab in the GUI).
The curve editing GUI is not the easiest, but after some time I got used to it.
Here is ...
In case anyone ever sees this, I've settled on Micro as my $EDITOR and use fc when I want to edit a command.
It has a really intuitive interace with undo/redo, cut/paste, and find/replace. Unfortunately I still cannot drag text and the UI is still not 100% as friendly as non-terminal text editors.