Filburn already uses magic to buff himself in combat, and the real "schticks" of the Magus is delivering spells with their weapons and attacking in the same round as they cast spells, IMO. A Blade Adept Arcanist (using a Black Blade) does not really do those same things. Instead, they are gishes in the more traditional sense - buffs and the occasional spell thrown at the enemy. In this respect Filburn would keep doing what he has always done - cast self-buffs and attack the enemy.

If people don't like the idea of such a transition, I won't push the issue. I present it as a way to better tie the mechanics to the fluff of Filburn's campaign trait.