Personally I think the identity of sword and bow should be separated and differentiated, as of right now there's literally no reason to use sword since the bow deals +1 damage and is exactly the same
You could maybe make it so sword builds are better when breaking armor, or inflict bleeding DoT effect, while bow could be better against naked health or inflict poison. Another idea could be to make sword better against multiple enemies (by allowing cleaving/multi target) while bow excels against single enemies (by increasing crit chance and damage)
Then you can work around the skills to better reflect these changes. For example, a skill that for each point rises sword damage against armor by 10%, up to 3 or 5 points. Or a skill that for each point increases bow chance to inflict cripple status effect on enemy by 5% per point up to 5, reducing their damage dealt by 25% when crippled.
Dont also forget to include a skill to increase survivability, like a 5% extra armor per point when shielding up, or a 3% extra health on total
In my experience with this game, since damage doesn't increase very much overall it's not worth to go for offensive strats, so building defense is always my go-to. Saves money spent on potions or sleeping and reduces time lost on meaningless deaths.
Another skill that would be highly appreciated is increasing maximum stamina. It feels very awkward to do three actions per turn and always waste the extra point, and even if you equip the amulet with the card for one extra point, it's not worth at all. It basically allows you to do one extra action for a total of 4, but only if it's the healing action, and meanwhile it's a card slot that's being occupied and reducing your options. With battle systems like these, you want as much card cycling as possible, and decks with few powerful cards instead of a lot of rubble to skim through. But the game doesn't let you optimize since stamina is stagnant and you barely get to call it "deck building" when you only gain 2 extra cards in the whole game. Since the second issue could be solved with further content additions along the story, that leaves the issue with stamina, and I believe this new skill system could do as a means to allow a little extra push towards satisfying combat without completely breaking the game.