What's wrong with this:

For normal driving, use right foot only for both brake & accelerator, just like a manual.

For slow speed manoeuvres like parking, have the left foot covering/using the brake, right foot on the gas.

This way, it replicates driving in a manual:

i.e. for slow speeds, the left foot pressing down means slow/stop, same as pressing on a clutch with the left foot, with right foot on the gas only.

Normal driving is also the same as manual, except the left foot doesn't have to operate the clutch.

That's what I use when I reverse into the garage or any other slow speed manoeuvre: with the left foot covering the brake pedal there's instant response available if something happens.

What I don't feel comfortable with however is left foot braking when driving normally at speed, I'd probably send myself through the windscreen!

So I'm guessing that those who object to left-foot braking are referring to using it when driving it at speed when it would be unnatural, especially if you're used to a manual.

That shouldn't prevent its use at slow speeds like parking, which is where many of these accidents happen.

If you learn to drive on an automatic car, so that you're only licenced to drive autos and only ever intend to drive autos, then left-foot braking would be OK. In the USA and Canada, at one time, 80% of cars were automatic and most drivers never drove manuals.

But if you EVER intend to drive manual cars, then Always use right foot braking in an auto!!!

And if we were to change like you prescribe there would be probably 10,000 deaths and people will blame you for your given advice.

"Some drivers condemn left foot braking on the basis of their own lack of coordination, entirely forgetting that other drivers are much more coordinated than they are."

If 'proper' left foot braking requires such a high level of skill, perhaps it should be left to rally/stunt drivers & not be recommended to the general public then?

" But if you don't left foot brake while manoeuvring you do not have full control of your car and stand quite a high chance of killing a spouse, child or grandchiled. "

But to quote (slightly!) - some drivers condemn right foot braking on the basis of their own lack of co-ordination entirely forgetting that other drivers are much more co-ordinated than they are - at manoeuvring with their right foot on the brake & using idle creep when reversing - i.e. the safest way to reverse an auto, especially in confined spaces.

"About 100 people are killed that way every year. And guess what? The drivers who killed them almost invariably blame their cars."

But how many would be killed (if those figures are correct) using the much more difficult technique of left foot braking in those circumstances? Or indeed, how do we know some of the above weren't using left foot braking at the time? Or how many would have happened whatever the technique used (in auto or manual) & were simply accidents of temperament & ability & not driving 'technique' employed?