1. When someone smacks your hand hard, you lose control of an object. The same applies to the force. A sudden change in the object or some thing with a high velocity is harder to handle than a nonmoving object. In that way, if someone smacks the saber while in the air it'll be harmlessly knocked away and leave the attacker totally defenseless.
2. "This weapon is your life." Throwing your saber is VERY dangerous. All it takes to lose is to have your opponent bat away the saber and charge you.
3. A saber blade is massless but it requires a lot of heft to cut thru solid objects. As far as we've seen, all object rotations with the force are very gentle and outside of combat. It's very likely that using the force to manipulate anything other than to just moving it requires more concentration (which isn't something you can do in combat)
As such, the best solution is probably to have a set thrown flight path with a minimal amount of force abjustability.
---Jedi Guardian of the Newbie Questions
---Masters of the Force Team Leader / Creator
---Open Jedi Project Lead Moderator / Co-Founder