Interesting, I haven't noticed this issue, but I use my watch on the same hand that changes gear (at least when I'm in a country that drives on the right, which is most of the time), so I guess I'm used to having that hand off the wheel fairly often anyway.

(Edited to add: I just went for a drive and paid more attention to how I use the watch with Maps, and I don't take my hand off the wheel if I'm just looking at the directions. Rotating it towards me quickly is enough to get the screen to wake. I have the Series 6 where the screen only dims and hides dynamic information when 'sleeping'. Maybe older watches where the screen actually turns off & on have a higher threshold before they wake?)