1. Make elite counters for XP level 3 and 4. E. g. the Germans can get SS counter colors, the Russian can get Russian guards colors etc.
2. Show dots on the symbols to indicate the level. These will only be shown at zoom level 3 because ZL2 is too small to distinguish the dot details.
a. Number of dots shows XP level:

b. Color of dots shows XP level:

No dot = 0, Red = 1, Orange = 2, Yellow = 3, White = 4
c. Shape of dots shows XP level:

No dot = 0, circle = 1, cross = 2, triangle = 3, square = 4
Location of dots can be discussed as well.
Is this something you would appreciate to have or will it only clutter the map even more?