It isn't too difficult to get above 20mpg. I was in the high 16s before the start of the summer and decided to change my driving habits. The past 1500 miles I've averaged over 20mpg with probably 85% city driving. Eco mode does make a difference for me.
I've thought about this too, thinking maybe putting a small strong magnet on the steering column where the ignition would be. then just hang the key there
It isn't just the driver door either. I was loading up with it running and had my door open to avoid the honk and my wife got in the passenger side and closed the door and it did it. This is nothing new though, my wife's 2016 explorer does it as well.
Those look sharp. I wouldn't change the stock ones out but the rear ones cake up with snow and ice so easily I can never open the rear door. These look like they would solve that and look better.