Does your door sensor show up under "accelerating" option instead of open/close? Did you try that and see what it does? I suspect that will work for getting a quicker/faster opening signal, but might mess up the "turn off when" part so you might have to split the rule up.
Also, how you mount your sensor is important. If you mount it at the very top of the door, it will move sooner than if you (like I did) mount on the 2nd panel down. I did that so I could crack the door and not trip the sensor when I am working in the garage.
To directly answer your question, I am doubtful they will add the opening capability to Simple Automations. See Bruce's responses here:
