With as much effort as it takes to farm Darkmoor compared to The Rat and Baba Yaga, it makes sense that the gear from Darkmoor would be just plain better. That being said, I'm hoping KI gives it another look so that it is at least better under some situations. Here are some specifics:
Majoris Helm of Cohesion vs Darkmoor hat Net benefit: +3% damage. Net drawback: -49 health, -2% power point, -1% pierce, -33 critical, -5% shadow damage.
Majoris Gear of Cohesion vs Darkmoor robe
Net benefit: +119 health, +122 block, +24% incoming heal Net drawback: -11% power pip, -7% resist, -10% accuracy, -96 critical, -19% damage
Majoris Runners of Cohesion vs Darkmoor boots
Net benefit: +308 health, +1% shadow pip, +97 critical Net drawback: -3% power pip, -5% accuracy, -3% pierce, -105% block, -1 resist
The hat in particular looks just plain inferior. Robe and boots together are roughly a wash for critical and block, and offer some health and a good amount of incoming heal. The enormous dip in power pips, accuracy, damage, and resist make both items even a bad choice in pretty much every imaginable situation. It'd be fine for these items to remain worse than their Darkmoor equivalents, but could they get a boost so they're at least within a couple percent?
Also, please keep this comparison in mind when itemizing Mirage.