Proposal
Add two buttons on the bottom left and right of equipped weapons that can be cycled through. Each button would be able to change a vanity aspect of the weapon, particularly where it is sheathed and its holding stance.
Details/background on your proposal
As it stands, the ways you can hold or store weapons can be seen as boring or problematic, For example, the Sunken Sword doesn’t pair well with many capes, as it clips through. However, this suggestion would attempt to alleviate that by appeasing both parties of “I want it on my hip” and “I want it on my back”.
Each weapon would have different choices, with particularly large weapons only storable on the back. You would also be able to change the directions of the weapons. For example, Atlantean Greatsword, despite not going on the hip, would be able to be changed from facing to the left to facing to the right. Additionally, again as an example, Sunken Sword would be available on the Right Hip, Left Hip, Right Back, or Left Back. Dual Bronze Flintlocks would be available on the Torso or Hips, and Plunderers would only have the one sheath position (Torso+Hips).
Furthermore, I propose weapon stances to help with the cool factor. For example, greatswords would be available in their current “Side Stance”, or a “Front Stance”, where the weapon would still be held with two hands, but it would be positioned to the front, pointing out and up.
Reason to add/change
This is a vanity feature, as weapons in certain positions could interfere with people’s outfits. The feature would help fix that, allowing people to have more freedom in their weapon stance and their sheath positions.
TL;DR: Add weapon sheath position and weapon stance changing. These would be exclusively vanity.