Dueling with friends

A system should be implemented to allow duels between clan mates. No rewards necessary, just a simple duel between friends. A person could challenge a clan mate to a duel to see who has the better base or to find out how they would match up against that type of base. This could even be used as a form of training for the more experienced players to teach greener players how to properly attack a base, for clan war or raid purposes. The player would have a small bit of text added to their profile showing how many duels they have won and lost. These duels could be watched live by fellow clan mates and replayed as well. The duels would be the same length of time as a standard raid.

This is actually an idea that I disagree with. Yes, it will help in practicing for attacks in clan wars and training new players, but one of the great things that makes COC fun is that you never know how it will go.
The game is already swayed in the favor of the attacker, a practice option will remove the defensive tactic from the game entirely.