That sounds really cool but I have to reluctantly agree with the senior: a cartoonish day/night sky is better than a half-implemented realistic one. I say “half-implemented” because it sounds as though yours didn’t account for local weather and cloud cover, which is reasonable but then incomplete. Even if you did, well, it’s turn-by-turn navigation. I expect the sky color to be selected for ideal contrast with the important UI elements to reduce the time spent looking at it while driving.