Would you like an in-game parser?

[Reynhart]

Actually. Many openers/rotations often comes from parsers. You know dervy? I'm well aware you know who he is. Do you wanna know something? He spent HOURS, I talk HOURS 6-10 hours a day finding out whats good on DRG, crit, det,skillspeed etc you name it. All this info came from a parser, believe it or not.

He could have done it by potency alone. Since potency is linear, any bonus granted by stats will always affect your skill in the same way.

Little example:
Let's say you play PLD and you try to find when is the best time to use Fight or Flight in your rotation. You know your potencies, you know that FoF add +30% damage, i.e, +30% potency, for 12 GCD, and you make a spreadsheet applying FoF on different skills. And, voilà, you have your optimal FoF usage just before Goring Blade, because it's the only way to apply it to two Goring Blades. Or you can do the same to know when it's better to change Oath, or how many GCD at least you need to stay in SwO to compensate for the two lost GCD, etc...

Dervy's rotation would have been the same with a ilvl1 weapon and no other gear. And I'll actually try something a little different from him tonight to see if I can gain this damned last 1% I lack from my latest SSS tries