I would suggest removing Acharnes, noone ever thinks Acharnes is a city, it is indeed technically in Athens. Add a city in Macedonia or Thrace maybe? And if able, also change the colours as well?
Indeed, it really is just a big suburb of Athens, which is actually to the north (not the east) of the city centre. I agree it would be better if it was removed altogether and replaced with some other city (Rhodes might also be a good idea).
Acharnes is west and not east of Athens. It's also a big suburb, not really a separate city. You can add other cities like Trikala or Serres who are also big.