These are improvements I would want to the clan system:
Allow players in the clan to request and donate supplies to one another.
And maybe give a crystal reward to players who donate, like 10 crystals per supply
increase the maximum amount of players to 20.
Although not everyone may be able to participate in a clan battle, most of the time, only a few players are online at the same time anyway.
Allow members to receive a crystal reward each day depending on their clan position (Must participate in at least one MM battle during the 24-hour time period from server restarts).
Supreme Commander; 1000 crystals
Commander; 725 crystals
Officer; 550 crystals
Sargent; 400 crystals
Veteran; 275 crystals
Private; 175 crystals
Novice; 100 crystals
Allow members to receive a weekly tankcoin reward (must participate in at least 10 MM battles during that week).
Supreme Commander; 50 tankcoins
Commander; 35 tankcoins
Officer; 25 tankcoins
Sargent; 20 tankcoins
Veteran; 15 tankcoins
Private; 10 tankcoins
Novice; 5 tankcoins
Allow players who are in clans to receive one extra star whenever they finish a MM battle.
Allow clan leaders (Supreme Commanders, Commander, and Officers) to buy crystals, tankcoins, or supplies for their clan members.