Personally, I think that a leader should be a team player because why would I do something that my leader isn't willing to do? Being a good communicator is also important. There's nothing worse than a leader who doesn't tell you when plans get changed. Someone who is organised would make a good leader, too. They should also be level-headed so that you can be sure that they are making the right decision for the group and have good moral values, so you know that all decisions they make are trying to do what is right.
To summarise:
- team player
- good communicator
- organised
- level-headed
- good moral values
I hope this helps :)