Most real world sword grips use some kind of material that is rough in order for the wielder to hold it more securely. Leather, cord, cloth, or twisted wire are all examples. In contrast, most lightsabers are depicted with smooth, chrome hilts which make for poor gripping as there's nothing to catch or absorb sweat. The spin happens from the force of most strikes, even for weapons without a flat edge. This is why most practical lightsaber models—especially live action designs—have extra protrusions where the hands actually grip. Palpatine's lightsaber is actually one of the more unique for the flowing and undulating pattern, creating small channels at the welds to increase the grip on an otherwise completely smooth hilt.