This summarizes my feelings along well. It's annoying enough that Frost Orb depends on the position of the mobs / boss...I don't really need a second ability like that with an even smaller AoE that I'm supposed to attack because...reasons...
CS is probably more useful for solo content from my perspective. TV works well in raid environments where I can coordinate with my other cooldowns to optimize with IV. But I would definitely take CS over PC.
PC is such a pointless spell. It's a button you press to do 10% more damage, expect instead of just increasing your damage you have to shoot a stationary crystal, just because.
What would make sense in the tier would be to keep Thermal Void as it is. A reasonable single target damage buff. Get rid of crystals damage split(and bonus damage) and make it a aoe burst talent, it would have no damage increase unless you could cleave at least one. Then also remove Comet Storms damage split and make it a sustainable aoe spell with only a minor increase in single target.
It's such a terrible tier, all talents basically do the same thing, a minor 2-5% increase in single target with only TV having some cleave potential.
Im playing arcane now, and PC is stupid op. Especially with the buffed supernova, it's ridiculous. 30% increased dmg is crazy (and if you didn't notice yes it's 30% for arcane/fire and 10 for frost), I easily crit over 100k sometimes with AB at 4 stacks.
It lines up perfectly with arcane power, the other two don't stand a chance in comparison. I use it at 4 stacks of arcane charge and with arcane power, and try to have 2 stacks of supernova...I usually can't fit all my AM's AND barrage in but I always want to use barrage since it cleaves. It's just stupid op lol.
Think of PC as the alter time of this xpac, because that's what it really is.