Yes ragers are strong, but WITH powers.

You take away rager powers and they become extremely sucky.
That is the main reason why ragers are balanced.

You take away scion or empire powers and it has very little effect on them.

A scion trying to get the sceptre from empire has very little concern compared to a rager.

You can not simply compare powers to powers because battle is so far below par *before* powers are considered.