[2022] Should we get new flags for Japan and Germany?

What you mention is a good example of "false memory".

War Thunder never was a " interwar/WW2 game". War Thunder started as WW2-Korean War game and after time we expanded to modern times.

If you think different, please show me some info on Sabre or MiG-15 participating in WW2, because both aircraft are in game since end of CBT

PS. I think sooner or later flags will be changed or adjusted in way, to fits more to more and more modern content.