NOTE: Before you post anything, I am aware of the addon which adds a shield to the default sword, read on before you jump to conclusions.
Basically, this item would be a sword and shield, and unlike the original, would have custom models and animations. I already have a shield model, if anyone is interested in actually going through with this idea.
Edit: I actually forgot to add the most important part. Timed. Combos. If you would just spam click, you would do a mistimed attack and it would do minimal damage. But if you timed your strikes correctly, you would do massive damage if every hit landed. And actual shield mechanics other than it blocking any loving projectile it comes into contact with. Right click to block, as people attack the shield, you take no damage, but a stamina meter (Optional, but would be cool) would go down, and if it was empty, you can't block.
