A little overpower, especially in terms of offensive expertise. It definitely makes the game easier if you base it on the balance of the original.

At first glance, it can make the game easier, and I think the power of expertise might require some fine-tuning (trigger-happy shootmen with reloading expertise have infinite damage). But like Vanilla Traits expanded, it makes some pawns noticeably worse--sure, in a big base of 10 pawns, having a single pawn with Critical focus on Art or Animals might not hurt as much, but it's also not going to be a big help, either--and that pawn's basically a hauler if they don't have high skills in other things.

i think it makes the game easier (when you disable critical passions to reduce other passionate skills) but it is not overpowered

what i mean is: easier is ok, because 1. it doesnt make the game trivial, just easier, so a hard setting will probably still be hard. 2. there are also mods which mostly make the game harder, and for me i pick a lot of mods that make thinks i dislike doing/managing easier and other mods, that make things i like to be challenged on harder and its one of those mods that makes skills more fun and 3. it is not overpowered because overpowered would mean, that it makes something overshadow pretty much most other stuff. that is certainly not the case as these skills still need to be leveled and you can only expertise one skill.

so i personally use it and am quite happy

definitely, unlock researching from inteligence and you practically beat the game