Additional combat perks sound nice but are there really that many parameters left which new perks could influence? I think TFP wants weapons to feel different so for example AOE damage in fortitude guns or a damage over time (like bleed, even if called differently) on a speer or knuckles would make the weapon choice less relevant.
And we have a class that would be impossible in your scheme: Select INT and you are the brainy type with gadgets and social skills. BUT he is no fighter and has a harder time in combat. Your separation would make such a weak combat/high social class impossible. You would need to balance all weapons so they are equal otherwise nobody would select the weak ones.
I'm not saying your scheme is bad. It is another scheme that would be quite possible, with some advantages and disadvantages. But also lots of work and difficulties to find more combat perks and something that would push release back another alpha. And the ridicule of people who say TFP rehauls too much would increase tenfold not that that matters much
But I'm not TFP. What I say is irrelevant and just guesswork. Just know that other forum posters have proposed similar schemes to TFP already and TFP did not adopt them (yet).