Ugh, i don't think thats a terrible idea however, i believe rdm's rotation should lose rng not gain it.
I propose Verwater(100pt) 15 >> VerBlizzard(100pt)15 >> Moulinet -30, scatter being tied to rng means that it's not fulfilling the purpose it's supposed to as an AoE Rotation but instead feels like an AoE alternative to jolt 2.
i.e scatter(100 pt) at 3 enemies is 300pt which is equal to using one cast of thunder or Aero but doesn't give the same amount of mana. so it's generally better to alternate til you can moulinet or manafication into even more moulinet.
Scatter 300 + Aero 300 + Scatter 300 + Thunder 300 = 1200 potency, while simply spamming scatter for the same amount of gcd's will net you 300 x 4= 1200 but significantly less mana.
however at 4 or more enemies scatter spamming is just better since that 400 per gcd.

My problem is that either scatter isn't worth using alone, or moulinet is too impractical to get to unless you prep it in your single target rotation. Using scatter to get to moulinet is just not smart, unless you're talking dungeon trash and even then you're using scatter because it's an Aoe filler, not because you want to use moulinet. tapping into melee routes and having an AoE rotation similar to samurai is what i'd prefer for red mage. making Ver Holy and Ver Flare AoE would be a nice change to make them more faithful to their original forms