I understand and agree with all your points. My thought was to drop crackle powder and Arc Cannon completly. Instead using Primal scar for the 3 turn debuff, Celestial Smite and Grand finale. Or song of storms.Song of Storms, Primal Scar, and Celestial Smite are all recharge powers, meaning they can not be used concurrently with Arc Cannon and Crackle Powder. Also, Celestial Smite and Primal Scar are level 6, which just factors back into how it takes longer to reach its normal state than Grease+Fireball. Oh, also, just ran a test on Celestial Smite theoretically stunning enemies impacted by Crackle Powder.
This was meant for a lvl 6 build and it is, indeed, not feasable for a playthrough build, unless you power level in the forest. I found that aoes arent that good later on. This is why I opted for purely single hits. I rather have 2 enemies dead and 3 alive, instead of 5 enemies half dead and no aoe's left.
The idea was to use the Leanenstone as a permanent substitue for arc cannon. For the situations when multiple enemies are low on health, but no aoe's are availabe. Basically an okayish aoe that doesn't cost a power slot. Early game money can be very tight, but during mid to endgame money shouldn't pose a problem at all.The leananstone is a decent enough aoe item, but it is an item, meaning it can only be used by the champ. CP and AC have the same cooldown, so there's never really a time where you'll use a Leananstone over an AC if using with CP, unless you just don't have the Arc Cannon. It can be a stop-gap of sorts until you reach the Arc Cannon, I guess, though at 80 electrum for a single one, it's a bit pricey for the early game too.