I actually tyring to figure out this one. is DET ay better than Spell Speed? You seem very confident that DET is better.
I did some test myself. It seem that both stat ... doing the same exact result on my parser. But then again, maybe the parser I use is not accurate.
One thing that could make DET better is the fact that afther a hundred cast of Cure, you will maybe save some mana.
But like I said, I base my observation on my little home testing. I could be wrong. But isn't it better to be able to land your big heals faster?