Card potencies (class specific)

[Shurrikhan]

I would say that Arrow for BRD is almost as potent as Balance.

While you wont get the damage to any of your oGCD skills, what you will get is a change in the # of Heavy Shots you can cast in a single target rotation. This will equate to a higher chance of getting Straighter Shot procs.

Getting extra SS procs allows you to replace a Straighter Shot with a Heavy Shot (+10 Potency) and a Heavy Shot with a SS Proc 150 Potency VS 140 Potency * Crit Multiplier.
So not only does get you extra damage, but it also greatly increases your average Potency/s for the duration.

AOE is pretty nice too for quickly multi-dotting + AOE Spam.

In pure AoE where you won't run out of TP Arrow and Balance are basically identical bonuses. In any other situation, Balance is noticeably superior, especially if you have oGCDs at the ready.
Getting in an extra Heavy Shot, a filler of 150 potency—with a 20% chance at triggering 60(1-<Crit Rate>) relative potency bonus damage on a following filler GCD—per 18 seconds / rotational string, does not make up for the lost 10% damage of that whole string. That'd award you around 157 potency at a 30% crit chance (40% with SS). Compare that to the minimum 162 weaponskill bonus potency of Balance:

44 + 41 + 15 + 15 + 15 + 15 + 14 ;

starting the string with IJ increases that by a further 9, and each Straighter Shot produces a relative 6*(1-<crit rate>) more bonus potency.

plus 10% of all oGCD and AA damage dealt).

Arrow's anywhere from 93% to a mere ~50% of the bonus of Balance when not locked to filler damage (as in pure AoE — Quick Nock/Wide Volley spam).