SCH's didn't have raw power. A number of the classes don't rely on raw power but rather versatility and what you clever use of the power you have. This is a point I make about MCH. MCH use magitek and unlike the Garleans, Ishgardian magitek integrates a Machinists own Aether into the tech allowing them to make their tech adaptable and more efficient. Its in it's infancy but in a way MCH are literally gun mages. If they can use Aesthetically charged tech the potential things they can do with it is pretty interesting.

Its worth remembering about BRDs as well that they aren't just singing nice songs. Their song is magical. There is a reason it drains their mana. This is actually pretty established in FF14. Do the lvl 60 BRD quest to get a prime and quite obvious example.

I guess the real question here is how are we defining strength? Raw power? Potential strength of application? Adaptability?