PandaBearCat, have you tried using the 2.0-2.5 damage formula that Puro and I came up with? You can find it "somewhere" in his excel file.
That formula assumes that 1 potency = well, 1 potency, so just multiply the result by the ability potency to get the estimated mean damage/healing.
The formula was originally designed for spells, but it does work for weaponskills as well. There is a different formula for autoattacks, but I do not recall where it is.

I am curious if the general damage formula itself (or the most accurate modeling setup) changed in 3.0. My blm is closing in on 60, so once I have a decent spread of gear, and time... lots of time... I can redo the damage formula modeling calculations to see if we can get a nice accurate model for our 3.0 needs. Something that should work for spells, healing, abilities, and weaponskills. Pretty sure AA's follow a different formula even after being normalized to a 3s attack speed.