How is "owner" really different from "leader"? It seems the system works fine as-is, so long as the leader does not appoint other leaders that are going to be problematic.
In reality that has not happened, and won't happen. There will continue to be cases that this can solve.
The owner is different from a leader in the permissions they will have. Some things I suggested that only the owner would be able to do:
Able to promote members to leaders.
Able to demote leaders to members.
Able to kick leaders.
Able to give ownership to a leader.
Able to change clan details (name and tag).
Able to "revive" the clan. (Join it while empty)
So basically the owner has power over the leaders and members, while the leaders only have power over the members.