For what it's worth, my preference would be to limit each song to a specific power combination - at least for leaderboard purposes - so that players have an opportunity to practice and improve with every power, and they are all useful.
The chances of being able to balance all the powers is very low, what with them all being so different.
To save everyone's scores being lost or wasted, have 2 sections to the scoreboard. 'General' where any power combo is allowed, and then the song/power specific one.











