It's still worth at least going into Swordmaster though. Astra and Sword Expert and nice skills, especially Astra.
Heck, I sent my Magic-based MU into Swordmaster just because Astra is awesome.
Then you class them out of swordmaster.
Yeah, I know. I'm just pointing out that SM isn't useless. Outclassed, but not useless.
They do have the Myrmidon/Swordmaster only 1-2 range Physical Sword(Amatsu) available for several chapters before Assassins can get one(Ragnell Just before the final chapter but high DEF units like Great Knights make better use of it), which means one of your characters is better as a Swordmaster than Assassin for the main game.