That Autostop Eliminator looks promising. That said, I did the software hack on mine. And it does not have to be disabled, my switch still works, just the auto start/stop is now off by default when the vehicle is turned on. Can still press the switch to turn on/off at will. If I were looking for a solution now, I would give this product a try. As they rightly point out, tampering with the vehicle software can be a warranty issue.
I've played with it quite a bit in the 8 months I've owned my Expy. It's very annoying and is not smooth like it should be, or often is in smaller cars. However it's quick and does not really effect driving much if at all. And yes, it actually does make a noticeable MPG difference under the right conditions. I've found that situations where constant stop-go like construction zones, parking lots, school drop-off/pick-up, etc.. the autostop is more of a nuisance and is actually detrimental at times if the stops are frequent. Likewise on highway driving, road trips, etc.. it's of no real use. City driving, slow and go, California normal, urban rush-hour type stuff, it makes a lot of sense.
There are actually no laws in the US or Canada that require this auto stop system. However, there are requirements for efficiency, MPG, emissions, etc.. and manufacturers are graded on a points system across their entire fleet of offerings. Systems like this can boost MPG under ideal conditions and help score points in favor of being efficient.
Too bad the switch can't remember the desired setting without a mod. We have two other cars with auto stop and one can be enabled/disabled at a toggle switch. The other the default state of on/off is set in the display menu. Also frustrating that the Expy doesn't remember drive modes... We had a '14 Explorer that was the same... Various drive modes and no memory when the car was turned off.