These are all good points, which I all agree on, but when talking about elemental's mechanics, first and foremost you need to address the real elephant in the room - inconsistency in damage output.
There are some clear markers that this spec's development philosophy is still going to be centred around getting crits, overloading those crits and possibly multiplying them with a dice roll hit. That in and of itself would've been fine, if only elemental's _baseline_ (no procs, lucky crits streaks/overloads etc.) was balanced to be on par with others. It is not and it can not ever be, precisely due to the way Elemental Fury and various talents/procs/what-have-you (god only knows what is waiting for us down the line in azerite gear - I'm already trembling in my boots) interact with our spenders.
Earth Shock and the way this ability interacts with Elemental Fury and the newly 'redesigned' Aftershock is the prime example of what I'm talking about.
For the sake of argument, let's assume it hits for 5k at fixed 60 maelstrom cost, crits for 12.5k, then you win a dice roll and it crits again for 12.5k STILL at 60 ms cost. 5k output vs 25k, plus additional mobility gcd, granted through sheer luck, out of my control and due to no ability on my part. How is that not THE OPPOSITE of engaging game play?
What this abomination of a talent also does is limit the baseline scaling that our spenders can receive, because if you wanted to tune the aforementioned to do really good damage regardless of whether you chain crits and rng on top of them, you'd have to tune AfS to sub 10% values.
Solutions? Either return the talent back to a fixed maelstrom % refund, or scrap it and come up with something engaging, not yet another dice roll. That, or tune its counterparts to be competitive options on their own, not reliant on picking other talents (hello, MotE is useless without EotE - that is how you create cookie cutter builds).
Our aoe spender looks even worse as far as consistency of output is concerned. Not only does it have the same daft interaction with AfS and other factors already mentioned, but now you've decided to also decrease its CPM, while (I assume it's still coming) increasing its DPS.
That would be fine, if you also increased its radius and/or tick rate. Leaving the spell as it is currently, while effectively cutting its CPM by half, is beyond idiotic and inapplicable in any conceivable aoe heavy scenario, which almost always involves the mobs moving, either into position, or being kited away/out of something.
Another issue is not only the baseline speed of resource generation via CL, but also the way it interacts with mastery, which iirc is 1/5th overload chance in a 5 target scenario. I don't know how High Voltage works, because it is bugged to hell and back at the moment, but I assume it's going to be like half of base overload chance, which would be what.. half of 1/5th.
Thanks very much. I also want to thank you for presenting me with 2 other very splendid options in that row to choose from. A 2.5min cooldown that is currently broken, as mentioned in the OP, and LMT, which is atm undertuned and suffers from the same problems our spender does as far as its static nature is concerned.