I like the idea of this mod and the amount of content it hopes to provide but I'm concerned about some of the core design philosophies not doing what they intend.

The changes to weapon proficiencies applying a penalty is not an ideal change, and neither is the separation of stances for fighters.

Since the fighter has fewer build options I understand wanting to give them more, but if you split the stances up it means you can't spend points on the additional abilities given to them if you actually wanted more stances. Which makes fighters point starved. Unlike casters the stances and most of their abilities are less active which means they're still not as fun to play even if you have more things to spend points on.

By all means give them more stance based specialization, but do not require 3 points just to get the basic ones. Leave it as 1 point for all three, then spend points on specializations. Since those already cost more points and are already going to lend players to use some over the others. The problem really is that you've now increased costs and removed player choice. If you're going to increase costs at least keep players with lots of choices.

Speaking about player choice, applying penalties to weapons without specializations is a related problem. Already the play pattern is to only equip weapons of which you have specializations because you get the additional abilities. If you also give penalties it makes the Devoted fighter subclass less special, and also means players feel bad about picking other weapons instead of just making an actual decision to use a non-specialized weapon in a good circumstance. Now that decision doesn't exist. There's no gain to this, only a loss.

I'm all for more options as is any one else, but applying penalties, and splitting up abilities giving the illusion of options really only serves to reduce options and player choice. I would rethink this design.