An intriguing concept, and definitely another mechanic that would make the game unique. I fancy the idea.
This is one of the things I really hoped for when I saw the teaser.
Begin able to design your sword from longsword to broadsword and such. Putting weight on either the tip or hilt to make it either be slow but with a heavy punch or begin really easy to handle. Really hope it’s not a damage system like the one in skyrim, where some weapons do more damage than others even though they look completely alike.
Hope you have the ability design it to match your preferences. Heavy, light, long, short, etc.
Having modifiers for how its shaped. Like you can’t have a 2 meter long heavy sword that is really quick and easy to handle. But if you’re good and carefull it be really effective if you hit right. But not easy to parry with. Or having a really light sword so you can quickly stab people, but begin so light, stopping blow from a heavy sword begin unlikely.