I'm playing a halfling ranger with Shot on the Run and I use Sniper Shot a lot. It is an effective ability with a reasonable cooldown. However, Aimed Shot is very dependent on rolling a critical and unless you're using Archer's Focus, more often than not, Aimed Shot gives you no real benefit for an ability on your quickbar that has to be pressed every time to use it.

Sniper Shot:
+2[W], +4 Bonus to Hit, +2 Critical Threat Range, +2 Critical Damage Multiplier

Aimed Shot:
+10 to Hit, +1 Critical Damage Multiplier
(If you are in Archer's Focus Stance, gain 3 stacks of Archer's Focus)

Since Aimed Shot is not a passive or a toggle on your quickbar (which would be nice as it would give a +1 Critical Damage Multiplier on your bow), then I think it should have a constant ability as well as the boost if you roll a critical. For example, Sniper Shot has a constant +2[W] no matter your roll, why can't Aimed Shot have a +1[W] for it's constant effect when pressed?