Ok, so Red Mage didn't quite work because they were "ok" at both Black (Thaum) and White (Conj.) Magic. That class would work well without a Base class because it doesn't fit well into the 30/15 rubric.

Blue Mage is sort of a Variant of Red Mage:
Sword? Colored robes? Magic? Check All

Blue Mage could benefit from this Class-Free Basis.
A Blue Mage should work like a Crafter/Gatherer, like a Fisher in a Sense, by Observing/Experiencing Powers/Attacks and Recording learned Monster Powers in their "Observation Logs". These could Progress using the Desynth % and Level Tables.

Certain Fates, Dungeon Bosses, and Hunt monsters would be listed as "Green" or even "Blue" Recipes/Catches, following the Four Star System.

Blue Mage would use Actions & Traits: Additional and fill the 10 slots (1 slot/5 levels) with whatever monster powers they had learned, supplementing base Job powers (Like Scan and Stealth).