@Pinworms

5 DET equals exactly 1 INT

1 INT can add anywhere from +0.15 to +1.9 damage depending on spell used (see spread)

There is zero obligation for you to max out any one stat (unless it suits your style or if you have OCD towards a stat). My BiS gear options simply shows the differences between each stacked stats (DET vs CRIT vs SSPD) the game has to offer at its current state. 99% of players will go for a blend of the three, including myself.

Patch 2.1 gave more CRIT gear to play around with. Spell SPD will probably get more love next time around.

On the side note, call me crazy but I can actually 'feel' the difference of 0.03 sec between 2 gear sets. I probably am crazy.. :O