Transparency: Potencies and Secondary Stats

[MerleSirlos]

What is the problem with potencies? it's looks pretty clear, the higher the potency the higher the damage/heal. If you have an ability with 100 potency and one with 200, it's pretty obvious which one does more damage.

You are asking to get the info on how it will reflect in battle, but did it not cross your mind that it might not depend on your stats alone?
Like said before, if you look at accuracy, every fight has a different cap, because every monster has, for example, a doge value and you need a certain accuracy value to get past it in what can be a very complex formula. (including for example character lvl and acc but also target lvl and dodge)
Some stats like skill/spell speed are easy to see the effect by just looking at your GCD.
So in the end what you want could become a full database of every monster in game with their stats and the formulas used inside the game. In the end you will still need to do some math or have some tools do it for you.

Hitting a dummy and seeing how the damage changes sounds a lot easier