So honestly, if you're using these shots you're going to be leaning heavily on con-opp, hoping for bard sp regen, or potting. I'd say that it really kills AA for anything outside of using the Arrow of Slaying, and even then that's pretty sp-intensive. The sp issue makes it really questionable in spending in AA at all. The shots are great but what makes them work are Soul Magic and Moonbow. Without those I'm not sure how sustainable it is and if it's not sustainable that's a questionable use of 32+ap. Better to go deeply into DWS where the special shots have no sp requirement.
Edit: Looking at DWS as a 5th tier option there's a lot to recommend it as unbongwah pointed out. Head Shot may not be as good as Arrow of Slaying but it's still a nice option, Leg Shot is nice, Killer, Hunter's Mercy...tons of nice options in DWS where it would be easy to fill out the tree to get to Heavy Draw and Head Shot.