Wow, I just tried putting Hoarfrost on the nagakiba that I upgraded all the way and then never really used. It does more damage than the L2R2 from Moonveil +10 with 80 int and 40 dex. And it's actually insanely strong for AOEing trash, unlike the shitty L2R1 on Moonveil that stops at the first enemy it hits (which is weird since the R2 does pierce). Anybody playing dex/int definitely needs to try a weapon with Hoarfrost on it.
Still some situations where Moonveil is better though; Moonveil can hit flyers, does way more damage with a crit compared to the cold affinity nagakiba, and Transient Moonlight is both faster to execute and deals vastly more stance damage. Hoarfrost does stagger a lot of things, but I've never seen it break a stance.
I can't decide between cold and magic either. Cold only does less than 20 more damage on the L2, but it severely gimps the weapon for normal attacks, backstabs, etc. It definitely procs frostbite faster though, not sure if that makes up for it vs. a boss. I ended up sticking with magic for now just because I hate it when my backstabs leave stuff with a few pixels of hp. I've got enough equip weight to handle carrying around both Moonveil and the nagakiba though, so it might be better to only use it for Hoarfrost spam.
