I think there is a lot of threads and complains about the inactivity system and how they work but actually my biggest problem is that the users don't get any notification that their account is going to be deleted.

So my suggestion:
If gf can spend resources developing Ogame Api then I think 1 to 3 e-mails could be send to users before deletion (7, 3 and 1 day before).
(You alredy got the registration just copy it and set an IF)