I feel that I can use the mirror to avoid the blindspot. I do notice that the rear head rest compounds the problem. I also don't feel double checking the screen is natural at all. We could really use an audible warning if you signal and the car senses something in the blindspot.
The rear decklid is really high and there's no way to adjust your mirrors around that. It was the main reason my mother decided against Model 3: coming from an E-Class with good visibility, she just didn't feel comfortable driving it.
Here are some measurements from Car and Driver that illustrate it well:
My outgoing BMW 3-Series had more than enough trunk space *and* plenty of rearward visibility. Look, I love this car, and this is something I can (and will) live with, but I still think it's a design flaw.I disagree. The cargo height is minimal for my purposes as it is. I will live with the compromise of reduced visibility.