Yes, I have actually seen the Atlatl in action. So, I think I can comment on the weapon. The spear is rather long and does need some space to launch it.
There is a significant amount of human body motion required to get this spear moving. As opposed to a compound bow or a crossbow launching an arrow. Either the compound or the crossbow require minimal movement to actually launch the arrow and there is more sound than movement involved. Consequently the deer doesn't "spook" or jump from the sudden movement of the bow user.
However, with the Atlatl, there is a step forward and the arm swing that is made to launch the speer. This is some significant movement.
It is my personal belief that this type of movement will cause a deer to "spook" and jump or begin to run, and accordingly, by the time the speer arrives at it's intended target, the target will have moved. So, you may have a clean miss, you may have a bullseye hit, or you may have a non-leathel wounded animal. I think you will have less clean hits with this type of weapon than any weapon currently allowed to be used.
So, Thats my thoughts, and I will continue to poke fun at this laughable proposal. Hence.....the bungee baseball bat weapon. Hey, at least the deer wont see you com'in!!!!
Dave