Why basic sage damage skill have 300 potency and astro or scholar have only 150

[Kenarashi]

So as a sage I have tons of damage skills but as a astro my basic skill does damage of 150 instead of 300 like sage. Also sage has couple more abilities that does damage as a astro i don't. It is really a pain when i try to solo older content or Fates etc as astro. At least white mages have blood lily.