I had been thinking that, I'm glad you confirmed it for me.  I am pouring over gem/enchant/gear options trying to see how to make it work best.  Your opinion on metas for arcane?  I've seen alot of posts pushing for the [Mystical Skyfire Diamond] and a very few advocating the [Chaotic Skyfire Diamond].  And, although it seems a bit odd and wouldn't be a dps booster, the [Insightful Earthstorm Diamond] would give back around 3000 mana in a 10min fight which could help a bit with the mana issues arcane often has.  Right now I think I'd likely go with the MSD, but I'd be interested in your opinion.

 I also have a ton of extra hit on my gear that can't be eliminated.  So I'm thinking of potentially leaving out some points in Arcane Focus that are essentially unneeded.   Any reason NOT to do this?