Honestly I don't see why people like non-rb missile (besides for pvp) because doesn't it only hit 1 monster at a time? While rb missile has splash damage and hits all monsters around it.
As for D-1 you guys know it has invinci frames too right? I think it's a little less than the missile's frames, but they're still there. And the damage I'm doing with D-1 is like 2.5k per hit with my 4.3k str o_o
And I don't know if it's just me, but I actually use Arta's 60 skills quite a lot (battlefield AND myth) it's one of the best pushing skills and it does (when maxed at least) 6k damage per hit (and S hits a lot) when you attack combo'd monsters.
Here's what I've come up with, but I don't have enough points to max the normal D-1 until I level some more or rb again later. Def getting twirling hammer though.