I played a Celestial Caster at 3 playtests so far, each with a tweaked build. My 1.3 character is a formal specialist with a 5th column and 65 formal. First playtest was a 9th column and 35 formal. I had lots of spells that were resisted through out nearly the entire weekend, except for when I used evocation. I was augmenting my storms and using potency, but the hit points enemies had still felt scaled for 1.3 rather than a 2.0 game. Second game I dropped down to 8th column and 45 formal. I didn't rely on take out effects assuming they'd be resisted and mostly focused on damage. Without the storm augmentations, storm spells are more of a liability since they make you prone and easily targeted, but they're by far the best use of 9th level spells in combat. For Seattles recent (omg so good)playtest, the build I went with had 5 1/2 columns with 45 formal and a 500 channeling pool. While the scaling of the event was amazing, I ran out of everything I could throw halfway through the big fight before logistics saturday, rendering me useless, and then I used 80% of my cards resources in the 1 big fight we had saturday night after logistics.
We had fewer than typical celestial casters for the playtests. My final analysis is that Celestial Casters have a difficult time ranking up as the burst damage class they're meant to as they don't have the sustain, and fighters are better damage dealers since they can swing/shoot damage unlimited all day long and burst with slays and eviscerates against larger enemies. I'm worried about lower level casters in the new system. Earth scholars heal and do straight body damage against undead who can't defend as well against healing. I wouldn't have lasted as long without the rituals I had available to me for sure. It's a very fine line that plot teams have to scale for in order to not hand out too many spell defenses for scholars.