I second the idea that sleep mode should be optional. For me, I only care about vampire drain when the car is plugged in. When my car is plugged in, I'm not going to use it for probably 10 hours, so any vampire drain is straight wasted energy. I don't mind wasting some energy to have the car ready to roll immediately during the day. For example, running errands at 5 different places where you're in and out in just a few minutes. I usually use the app to leave the AC running the whole time I'm inside the store. Hopefully there's a 10-15min delay before sleep mode engages, at a minimum.
Wasted energy is a valid concern. If you are plugged in, you will still have an adequate enough charge for your needs, unless you need a range charge and need to push it.
My concern was for the times when I'm NOT plugged-in. If I'm away from home and don't have access to power, I would want to save as much juice as I can. When I'm local, I wouldn't mind losing some range here and there in exchange for a rapid wake up.
Ideally, there should be a setting for "Allow rapid wake-up" or "Prevent sleep mode". There could be the standard disclaimer: "If you select this option, you may lose range while parked a more rapid rate..."
OTOH, if there cannot be a setting, I'd take this new feature over the old.