Again, arcane is superior to frost--especially since 5.2 with 26% spell miss on nova's and fireblasts.
Arcane can hardswap targets instantly, frost needs to rebuild frostbolt stacks.
Arcane has superior movement, frost needs to take ice flows to be viable.
Arcane relies on 1 spell with 26% miss chance for shatter which hits over 1k. Frost relies on 2 spells with 26% miss chance for shatter which hits under 1k.
If druids couldn't just shift out of roots and hit rating was fixed then frost would be an ok spec. Ok because it would be better at protecting your healers/fcs compared to arcane.
As for outcome of a game, arcane is superior for both pugs and premades. In a pug, you need to swap to whatever targets your bad dps decide to hit--arcane can do that now, frost can do that 6 seconds from now. In a premade, you need to swap to whatever target is called--again arcane can do that now, frost can do that 6 seconds from now.