Background attributes
It is typically said that backgrounds are supposed to be "starting packages", rather than "classes" that prescribe a specific "playstyle" for the entire game. But backgrounds determining your attributes is contradictory to that. Attribute points are one of the most permanent things in the game. They cannot be gained except by leveling up, and they cannot be lost. They cannot be rearranged except with Jiyva, and even that rearrangement is usually detrimental. Every non-Jiyva character is stuck with their background's attributes forever, and the impact of this carries into the late game, as str and int have strong, direct effects on spell success and spell power.
I think this is a problem. Backgrounds shouldn't have far-reaching, essentially permanent effects like that. Therefore, I suggest removing the background contribution to starting stats, so that species is the only thing determining your starting stats, and adding 4,4,4 to all species' starting stats. This has obvious balance implications, so here is the background list with the changes in starting stats that would result from this change:
Be is significantly nerfed. I see no problem with that.
Fi and Gl are nerfed. Ever since getting might, Fi has had a decent early game, and Gl's early game isn't awful, so I think this is okay.
All mage backgrounds are significantly nerfed. Since these are strong backgrounds I think that's fine.
Wn loses an axis of variance. However, I contend that this axis wasn't a satisfying one in the first place. Starting with no spells and all your stat points in int is not particularly fun or interesting.
So as a whole, balance-wise, this is a player character nerf that mostly targets strong backgrounds, and nerfs them for the entire game, not just the early game. That sounds like a good thing to me!
If you want to get fancier, the amount added to species doesn't need to always be 4,4,4. If DE are supposed to have really low str you could give them 0,7,5.
(Yes, removing attributes would solve this problem just as well, but that won't happen soon.)