I just had my two test runs with version 126.96.36.199. As I said yesterday I scrolled a lot around the map in 2D and 3D and performance so far seems good, also in settings menu. The icons (car or cookie) does not always seems to match what the program is doing, but I guess it's to enhance performance.
The issue with the screen going blank (more often in the 1.5x version) can be fixed with manually turning off the automatic screen rotation. However it should be in the waze settings, so you don't have to go always in the android settings to disable this feature.
Due to the not so detailed map data so far in Hamburg I never got the software to calculate a route, but today it worked for a short route. 4 km with 4 turns. It crashed after the first turn unfortunately. Log has been send by mail.
I will try the new version 188.8.131.52 now.
Btw, thanks for the sat data for Germany