We plan to offer armor skin swap and tinting in game, but the weapons animations have different speed and showing a two handed sword on your back changing into a one-handed sword during battle would be a bit strange visually. You'll most likely be able to swap the skin of your weapon with a similar weapon type, but considering the difference of size reflected in animations for two-handed and one-handed weapon, it is unlikely to happen, at least for the release of the game.