Heh, yeah. I stopped to play SO3 when the twist occured. Such a disappointment, and such a shame too as SO2 is so excellent.
I also dislike SO3, but for an entirely different reason: The dungeons. SO3 has, by far, the lamest, most boring dungeon designs I have ever had the displeasure of dealing with.
Every single dungeon is just a giant maze with nothing interesting to look at, almost nothing to interact with, the only obstacles being monsters that are too powerful to bother fighting for experience.
Which brings me to another problem I have with SO3: The monsters. Throughout the first third of the game, they're not too bad. Challenging at times, a breeze at others. But then they just went
BAM, tough as nails, take full combos from the party to die (each!) and can instantly KO any of your party members whenever they feel like it. And should you somehow manage to win against a group of these atrocities, they'd barely give any freakin' experience.
But as far as the story and characters are concerned, I found them both average. They're nothing I haven't seen before in JRPGs and, actually, interact more with each other than in most JRPGs I play.