Sorry, but no manufacturer is going to do the things you suggested, so they might as well give me the button.
Manufacturers already do what I suggested. Discrete codes exist for devices which don't have a discrete on and off button on the remote. Having an extra button is a kludge.
I would agree with you if it weren't next to impossible to get the codes even when they do exist.
I thought you just said that no manufacturer is going to do what I suggested?
If you're using a universal remote and have special profiles designed then I'd class you as an advanced user or have an advanced integrator that did it for you.