I agree with your point, but on this specifically I think there already is a feature in DCS that allows you to do that. If the module has keybinds for the ON position as well as for the OFF position, then you can bind the off positionto a button only found in the buttons list called "XXX_OFF".
That input registers the stopping of your switch. I've been using it on nearly all airframes, and allows you to set up a physical switch as a 2-way bind.
For example, you'd set the ON position to the "JOYSTICK_BUTTON_15" input (by hitting that button in the DCS bind menu) then the OFF position to the "JOYSTICK_BUTTON_15_OFF" bind, which you can find in the list right under "JOYSTICK_BUTTON_15".
This allows you to use your HOTAS switches as intended, on all modules that have ON and OFF inputs. If I recall correctly, in my experience only FC3 aircraft have come short in that category, and I've been able to make everything I wanted work on the F1.
A friend taught me this a few months ago and I couldn't believe it, it's a great feature and so few people know about it!