I personally think the single center screen will be a total non issue for the stock, and for customers. After reading endless posts here about it I recently did a long drive in my Toyota Sienna which has a normal steering wheel cluster, and a small center display for the heater/clock (Which is way farther to the center than the top left corner of the Model 3 screen). I spent several hours on the freeway looking at each of the two displays endlessly, and came to the conclusion that the ways your eyes work you have to take your focus completely off of the road to look at either of them. The idea that you can look down at your speedometer, and keep your eyes on the road at the same time is BS in my opinion. Your peripheral view of the road while looking at the display was almost exactly the same looking at the two, except you have a little bit less peripheral view to the left when looking at the center. It didn't seem like it took any longer to glance at the center display than the center one. Especially with the automatic collision avoidance features built into the car, even if it did take you s split second more to look down it will be a non issue. As far as monitoring what the status on the self driving system is doing, I suspect that people would be much safer just looking out the window to make sure it is on the right path. I could easily imagine a scenario where you are looking down at the screen, thinking "That isn't right" while the car proceeds to crash its self. Especially as the self driving gets more advanced, and is using all the cameras, radar, and sensors, it will be too much going on for our human brains to process anyways in real time, and we will be safer just watching out the window. The only thing that seems like it really needs to be on the dash to me is turn signal indicators, so the self driving car turning, or changing lanes doesn't surprise you, and a visible warning light to notify you to take over immediately from the self driving. Those two things could easily be accomplished by something as simple as LED lights embedded in a crease in the dash.
As others have mentioned, this reminds me of the iPhone 7 no headphone jack drama. I bought an iPhone 7 and thought the lack of a headphone jack kind of sucked, for about 6 weeks, until my back ordered AirPods showed up, then I changed my mind and decided I will never use another pair of corded headphones again. I expect it to be the same with the Model 3 display.