Replay button.

I should have elaborated more. As in the ability to watch a battle that your teammates or yourself have been involved in. Whether this be a watching a guild mates battle on offence or seeing how your team does on defence.

Was thinking the same thing. I'd say the server would keep a log of the battle events that could be used to simulate what happened.

Definitely a good idea

Replay would also give players more chances to spot cheaters.