One of the issues I have run into in several alliances so far is the alliance doesn’t view itself as a team and that players (mercenaries) are recruited or join just to battle titans and leave. This has continued even after Alliance Wars were introduced.
In my opinion, this undermines the team objective of the alliance. Why does a player not in an alliance have alliance energy? They are not choosing to be a part of one.
I would suggest one of two implementations:
If a players changes alliances, their alliance energy drops to zero. In effect, alliance energy is associated with the alliance you are currently a part of.
A player must pay 1 alliance energy to leave an alliance, and pay 1 alliance energy to join a new alliance.
The true mercs will still have the ability to do this using alliance energy potions. For most players, they will need to learn to work together.