Stat priority for a red mage

[TelosNox]

You still can prefer CRIT in general

Possible combinations:
CRIT + DH = Perfect
CRIT + DET = Not bad either
CRIT + SPD = Ok here we might consider something else but first we should check: Is SPD the major stat? Or is CRIT the major stat?

If you see CRIT + SPD then what else is available? For casters it's currently most time DH + DET.

http://ffxiv.ariyala.com/16ZIA
This is my current gear which I considered as BiS for SMN so far. You could avoid further 125 SPD by switching feet.
We can do some math here (expected dmg multipliers):
2085 CRIT = 1.116064
1727 DH = 1.08625
1498 DET = 1.072
Overall = 1.29961

With other feet
1987 CRIT = 1.109251
1772 DH = 1.089
1676 DET = 1.082
Overall = 1.30703

So average DMG per Hit would be higher.

Now we consider SPD
457 SPD = 1.005
582 SPD = 1.013

So if we multiply with speed:
CRIT Feet: 1.013 * 1.29961 = 1.31650493
Other Feet: 1.005 * 1.30703 = 1.31356515

Now it depends on how much SPD affects pets. Do they gain dmg by SPD? If pet is not affected by SPD at all, then CRIT Feet are a dmg loss because 30% of caused dmg is not affected by SPD. If pet dmg scales with SPD then only about 10% (Fester) of caused dmg is not affected and the CRIT Feet are a gain vs. the others.

As we are talking about RDM it is more clear:
Skills not affected by SPD should be Fleche, Contre Sixte, Corps-A-Corps and Displacement. That's about 20% of dmg done. So SPD only affects 80%.
According to this we adjust gain by SPD as follows:
CRIT feet: 1 + 0.013 * 0.8 = 0,0104
OTHER feet: 1 + 0.005 * 0.8 = 1.004

Overall:
CRIT Feet: 1.0104 * 1.29961 = 1.31312594
Other Feet: 1.004 * 1.30703 = 1.31225812

So CRIT feet should be better here for RDM.