Thracia is indeed a nasty title. It's good fun, but long ranged enemies are horrible. I've only cleared it once, I'm afraid to try again!
The scrolls mean that it's pretty easy to fix a character with one flaw. The Neir scroll got Lifis up to 14 BLD - He was stealing Daim Thunders ^^. Especially handy against a certain someone. Fergus is a definite use, his PCC really is great, especially with Karin around. I do agree with Wrath on Karin, it helps make up for her poor STR. I'd also like to recommend Hicks, despite his sword rank (which took forever to get to C), he's fairly durable and is a good candidate for the Master Axe.
DA125, no love for Sara? She caps magic, skill, speed and luck pretty quickly and has a wonderful skill set. She did wonders on Chapter 24x. Magic weapon levels don't matter too much. My mages (Asvel, Linoan, Homer and Sara) were doing well with Thunder tomes (which were plentiful and stolen!).