I also applied anti sieze the the splines on the drive shaft to ensure it would slide on and off easily going forward....you never know when you could get something stuck in the pump and have to pull it to clean it out(drift wood is a pain). No need of it being stuck on the shaft.
The edges on that impeller are a little rough. The impeller itself doesn't look too bad so you could probably just file the leading edge down a bit until it's smooth again.