Initially planned more changes (without affecting the core mechanics), but it turned out that implementing them caused the game to display things incorrectly and simply crash. I had to abandon the idea of having one button on the level-up box ("the wheel") for all factions (first screenshot showing level up). Furthermore, I abandoned adding a separate "skill probability" for each faction on the same level-up box. Perhaps I will add something in the future.
Changes related to the main mod can be seen in the screenshots below or you can download the original mod and compare.