Looking at the numbers: Aimed shot appears to only worth firing if we use Lock and Load.
Code:
Attack Power: 10000
Thas'doral WPD: 2752
Lone wolf 35%
Normalized Weapon Damage: 4752
Normal Crit
Arcane Shot: 8019 16038 10
Windburst 64152 128304 -40 20 sec
Marked Shot (n) 28868 57736 -30
Marked Shot (1) 29061 58122 -30
Marked Shot (2) 29253 58506 -30
Marked Shot (3) 29446 58892 -30
Aimed Shot (n) 16038 32076 -50 2 sec
Aimed Shot (1/n) 16680 33360 -50 2 sec
Aimed Shot (1/1) 16680 35028 -50 2 sec
Aimed Shot (1/2) 16680 36696 -50 2 sec
Aimed Shot (1/3) 16680 38364 -50 2 sec
Aimed Shot (1/3/6) 20529 47217 -50 2 sec
Headshot 115473 230947 -20
Sidewinders 19245.6 38491.2 70 12 sec
Lock and Load = 10% / 3 seconds to proc 2 Aimed Shots
Barrage 80832 161664 -60
- secondary targets 54562 109124
Murder of Crows 18775 -30 60 sec
This assumes procs for Hunters mark is pretty quick off Arcane shots.
Note: This assumes a completely filled out bow.