That's an interesting idea. To be clear, the part that was bugging me was the fact that the rotation gradually becomes slower as it approaches the cursor position, not the fact that it rotates slowly. I think it would be more sensible to the player if the rotation rate was linear. But with the way you described the "swinging" action you're going for, I guess the way you've done it encourages that more.
It might also be interesting if instead of slowing down it kind of overshoots the target and bounces back a little bit like a spring.