I had loads of difficulty yesterday finding a good group for nightmare, even with my 20k+ might light party. Eventually managed it, after changing out of dragon prep prints, except for the MUB Kings Countenance (for Annelie, who lacks the curse resist). I did the same today, but was still having difficulty, so I caved and raided my sunstone vault for the first time and used two to fully unbind and upgrade Cupid.
That really did the trick, team is now 21k+, and now Annelie is destroying with her DPS, what with ~40k (best before was #25k) damage on stunning display if I place it right at the break. Beat him the first time with 7 seconds to spare after doing this, in a 20k+ room. I think I'll be playing more than my single run each day now that I've made the investment, as it's much more fun to fight him in nightmare, and I like the idea of helping people get their daily bonus chest.
Edit: So far, I've gotten 20 succ dragonfruits + 1 twinkling grains, and then 1000 eldwater + 1 twinkling grains. Really jealous about all the sunlight ore and damascus crystals floating around. No vouchers in the drop list, but still I'm crossing my fingers to get at least a couple ores or crystals over the rest of the event.