[Callisto]

A haste build could solve some of your issues facing /DNC for sure, because the largest is definitely quick TP building, since you aren't usually getting Haste from a mage. You could fairly easily hit 15% equip haste with Dusk hands/feet, W. Turban, and Swift, although those are also slots where you could be stacking a solid 24~ Acc...this shouldn't be a huge deal with Sushi and average Hunter's rolls, you only need about 407 Accuracy to cap out hit rate on Colibri by my calculations. With the 15% Haste and 95% hit rate it'll take you about 40 seconds to get full TP w/ a Joyeuse on average(when you aren't being pulled away for Evoker's and whatnot), given the life span of an average merit mob that's about every other fight.

This would definitely put you into a pure support role, but I'm guessing that's what you're prepared for already. The main question I suppose is if it's worth giving up your DD potential for the MP-less support, and that really comes down to party setup. As /WAR last night I was averaging 1500 Slugs on Colibri, about 30% of the mob's health, and hitting as high as 2200 with full buffs. That's a lot of DD potential to be giving up.

In terms of larger events, one of my COR comrades in my LS is huge on /DNC now and usually uses it to most events, I suppose in larger fights you could still TP easily in your normal gear with Corsair Bullets(I know you have a heavy RAcc build, at least last I checked) and still be a reliable support with it, however in a fight like that I still would be inclined to use at least /RDM for the boost to QD, if not /BLM. In something with lots of small fodder mobs however, like Limbus/Dynamis it works very well.

Edit: Complete nitpicky sidenote, I don't think the Brutal is really neccesary, iirc more Double Attack slows down Joyeuse, but I might be wrong on that. 4 Acc is alot out of an earring, I'd stick with the Hollow + Suppa.