This. It's kind of annoying, because I used mostly Semry (a leader I got from the guild), McGrady (another leader), Torgal, and Rush.
In hindsight, this was probably stupid, but I figured I'd have to learn to depend on the grunts I could get outside of the main story, since you never know when you'll lose them.
Nor, I guess, are you ever aware of when you'll be paired, alone, with one of them. :\
I guess I'll try to level up, but then, since the enemies scale and she's quite underpowered, I don't think it's going to be any easier if I say, went to dillmoor or something and hacked away on guys over there.
It's annoying :| I wish those not in your party -- at the least the story characters -- can get better passively. I think our joint HP is like 800; not sufficient at all to fight the enemies at the opening to the mines (they hit for 400 or so with a move called Bodyslam or something, and it's not a move they're afraid to use, either!)