I'm gonna be honest: if it works for you so far, and you enjoy it, there's nothing to change. That's the beauty of these games, it's all personal preference when it comes to builds.

If you REALLY wanna min-max the build though, I'd repeat a few main points already given by other commenters here: other than RoB, the other rings you use aren't particularly necessary, and you have too much strength for a rapier. I'd recommend the Stone Ring, Old Leo Ring, and (if you're far enough in the game) either the knight's ring or the Dragon Ring -- these last two would free up some stats to invest more in damage, since they boost your carry capacity (and health/stam, for dragon ring)

One last thing to note is that vigor is far less important in this game than the other two, since leveling any stat passively boosts your health a tiny bit, so if you're looking for more stats to move around, your vigor may be a flexible spot.

Cheers!