This is a really unique plugin! I agree that it looks odd to have your sword chase you when you move. One suggesion would be to make it so that it only appears when you are standing still (maybe toggleable in config). In addition, perhaps make it so that when you are holding a sword in your hand, the sheath will be empty (also because it looks odd) Nice work though!
Pretty creative plugin, and quite frankly it is quite impressive as well.
One thing that I find mildly annoying, is that your sword will be floating behind you if you start sprinting or even walking. From the development standpoint, it is probably quite challenging and performance-unfriendly to find a better alternative but maybe you could work something out?
Regardless, impressive and a unique plugin that you could always consider adding to your RPG/SMP server to add some spice.
10/10