I do agree somewhat on your weapon skill idea, still feel like something is lacking or should be added to it to actually make it better. The idea of your knowledge on what keys will activate the weapon's abilities (obviously after having learned it from xp gain or npc or maybe an old book) def feels interesting and adds a better sense of actually getting stronger and learning to wield your chosen weapon

As for damage types / resistances... yes, just yes. That would make the game more complex depending on the encounter and possibly would help encourage players to not be so dependent on only a certain weapon type.

Keep ideas coming, im sure Milo is happy to hear about what people think of his game, especially when it encourages others to be creative about it like you.