Personally, I like personal weapons. In my hack around four or five characters have personal weapons. I don’t think you should give almost every character a personal weapon, look at the FE8 PME of Mangs. Almost every character has a personal weapon there. Although it is cool to see a lot of different weapons with a uniqe concept, it does remove the element of uniqueness some minor characters may have.
Though I have not (yet) played Thracia, I think I get the idea of how personal weapons are handled and I like it. Giving a character a personal weapon could help them get noticed by the player and make them more fun to play with. If a personal weapon is given to a unit in the early game, it might help creating a snowball effect: the player likes the weapon bound to the character so he uses that character more in combat, granting the unit more exp.
This reminds me a bit of what I like to call: semi-personal weapons. These are weapons like the silver lance most Jagens come with. They are not specifically linked to one character, but the weapon can only be used by one or two characters until the rest of the cast acquires the weapon level to wield them.
Conclusion: In my opinion personal weapons fit underrated characters and help them getting noticed. Semi-personal weapons make a unit stand out for a while, which could be enough to make them snowball.