Clans should be rewarded for game time spent and how dedicated they are to the game.

To do this AND improve the social aspect/banter in the game I have a second idea.

Battles will be a new form of attack and way to gain money/elix/gems as the prize.
The following formats are available...
3v2 4vs2
Rewards and administration
Clans leaders can register for these battles and vote on who wants to battle from his clan, whether for fun or for serious trophy gains. Maybe there can be 3v1 games, where a very high level players can battle three others sequentially with the same troops. Like a survival mode, but they can earn bigger trophies.
Matchup engine
The matchup engine should be bases on how many occupied squares there are between the clans or selected clan members.

this is where it gets interesting, opposing clans can have a joint clan chat for the duration of the battle. Banter and discussion are moderated by the clan leaders.
it is possible that naturally you may discover other teams, and there should be a JOIN button for the winning team in the joined chat available for a limited time after the matchup ends.

this way, transient players are the new resource and we can have GUNs for hire, people who can be in it purely to win gems but have to help those lower teams gain on the bigger teams.