Right now any team can attack any team. I was thinking it would be a good idea to put teams into Teirs (1, 2, 3, 4) and only allow them to attack other teams in that Tier. That way bigger teams can't attack lower level teams or teams just starting out.
It's very discouraging when a team with very high levels sets up a war with you when they have double the levels you do and 3 times the players, it's a for sure loss. To keep people wanting (and supporting) the game I think that would be a simple solution to stop people from walking away, maybe not from the game entirely but from starting up a team or joining one.
Just an suggestion.