Some thoughts on the new Engine of the Gods.
As many have stated before, the new Engine ability isn't all that good. It has some useful powers, but they're risky to attempt if you haven't stored up energy by not using it. So you will only likely get to use it's ability to heal itself a few times in the game, or maybe use it more aggressively once or twice if you don't have to heal. And it's no longer a priest. It's certainly not like the Engine of the past.
But it's worth looking at it from another angle. One of trade-offs. The Engine of the Gods is a Stegadon, for the same cost as a Stegadon, with all the stats and abilities of a Stegadon, with a few exceptions. First, it can't be battleline in a Thunder Lizards army. Second, you are taking the Engine instead of the Skystreak Bow or Sunfire Thrower. So you sacrificing it's ranged weapon electives for the chance to heal or maybe attack, etc. a few times a game. So I would think of it like this:
"For 300 points, you can take a Stegadon. It can be equipped with a Skystreak Bow, Sunfire Throwers or an Engine of the Gods. If you are a Thunder Lizards army, it counts as battleline unless you armed it with the Engine of the Gods."
That puts the trade-offs into a point-based perspective; the Engine should be arguably equal in value to those other two weapons, and isn't meant to be quite the mystical machine it once was.