See the reason I don't think it makes sense to completely bag on every new mechanic the moment they start revealing it is this.
Here is a reaction from when they started showing Jades:
And here is the same person weighing in now:
This is why I usually favor evaluating if the cards make sense in the supposed archetype, and then evaluating the full archetype at the end based on what the complete deck (as informed by the previous archetype-fit evaluations) would look like.
Going through this, I think the 9 drop is a harder fit than the 7 drop, because the 9 drop primarily favors fighting off aggro, and turn 9 is somewhat late for that.
However, it does let you potentially go face for another turn if your board is consistently better due to the mechanic, so that might make a lot of sense as a cover for your finisher. It's hard to say without seeing how many board flood Elementals there are. I agree it's the most questionable Elemental card thus far (along with Pyros, covered later).
The 7 drop let's you usually survive turn 7, which against aggressive decks, is much better timing. If you're playing it after Fire Elemental, you're getting a lot of board control to boot.
Pyros I feel I can't evaluate without seeing what Mages can use at turns 3 and 6, since you want to be comboing with a pretty powerful card to play something that substandard on curve.
The 1 drop seems to trivially fit with every Elemental deck as you can guarantee an activation for 1 mana while playing something else, like if you cast Fireball and the one drop (or the generated one drop) on Turn 5 to get a big Turn 6. The Priest Elemental is trivially good in an Elemental deck for the same reason.
Removal that buffs your mechanic has long been favored, so I can't imagine you wouldn't consider that Mage card unless everyone just runs 3 health and up minions early game. If we assume Jades exist (or other Elemental decks), there should definitely be two health minions on the board regularly.
Inherently you run anything that you were running before like Water Elemental and Fire Elemental.
Al'Akir might be a reasonable precursor to the 9 drop if you find yourself needing three Taunt plays in a row, though obviously it's hard to pull two legendaries by then.