I think that I prefer the Solar Engine unless Tehenhauin is involved - I look to the Vampire Counts' Bat Swarm as a key example of how making a Swarm better doesn't necessarily make it good. And I'm not sold on the Carnosaur when I can just take Sharpened Horns on an Ancient Steg and get a monster with superior all-around utility. My projected list at 2500 is looking mostly like this:
Proposed List - 2500 points
Core - 720 points
50 Saurus Warriors, Full Command, Spears
2 x 10 Skink Skirmishers
Special - 690 points
2 x 6 Chameleon Skinks
36 Temple Guard, Full Command [Slann goes here]
Rare - 460 points
Ancient Stegadon, Engine of the Gods, Sharpened Horns
2 x Salamander Hunting Pack
Heroes - 185 points
Skink Priest, Cube of Darkness [Lore of Beasts]
Skink Priest, Dispel Scroll [Lore of Beasts]
Lords - 435 points
Slann, BSB (Standard of Discipline), Channeling Staff, Harmonic Convergence, Soul of Stone, The Becalming Cogitation [Lore of Light]
Grand Total: 2490 points
I'm assuming that Skink Priests are the same points as they were in the old book (no one has said anything about that yet). The goal here is to generate massive amounts of attacks via Light buffs and Predatory Fighter (Speed of Light/Timewarp ftw), and use Wyssan's to give them some sting. I have a couple of points lying around which I'm not entirely sure what to do with, and I could probably use one more deployment drop (maybe trim the Saurus to 40 for another unit of Skirmishers, though that means I start losing attacks with casualties immediately). Either way, those are my initial thoughts.