Aha, I had not known about that trick there.
Well, went and had a look at them.... most of these still seem too high to me. Moonstone & sunstone just dont generate very fast at all. Particularly in the first half of the game. Sunstone in particular is troublesome, since it also slows down moonstone while being produced. Generally, I consider sunstone the most "expensive" resource in the game; all of the really powerful things use it (or should, anyway).
Now, one thing you could do is make it so that the 4 gods who can appear in the age of monsters have lower average costs for their units than the ones that appear in the age of gods; costs of 20-30 sunstone might make sense if it's the late-game-only gods that have those units. This would fit with the theme that the Japanese have of units that are really bloody expensive, while not being frustrating or useless due to cost. In the first half of the game, I'd say 10 sunstone is pretty dang expensive. Particularly when you consider that many of these units carry additional risk; for example Gagoze (I think I spelled that wrong) costs like 47 sunstone; I've never SEEN 47 sunstone in the reserves at any point. His cost could be muuuuuuch lower and it'd still work; he's got a powerful effect of shutting down production, but there IS risk with him; it wont turn back on until he's dead, and if he kills some units and levels up, it becomes harder to kill him without Super Smite or Shinigami; and using either of those is it's own additional cost. Or Akateko; this one could cost 5 sunstone instead of 27 and make sense. Sure, it can kill anything other than a god, BUT, the correct unit has to actually be the one to attack it, and on top of that it ONLY kills one unit at a time; you'll need more than one of these to make a difference in many battles.
Of course, there IS the fact that these guys also give a multiplier to the usual myth unit score, so that's a plus as well, but still, TOO expensive and that wont really matter. And note, I'm not saying that all of these should change super drastically in terms of cost; there's a couple that could do with a very drastic change (Gagoze, Nue), but others dont need to be changed THAT much.
That said, there are a few that should remain at their very high cost. Like Keukegan, who not only has a super-useful effect, but also gives 8x points, has no risk, and is then a decent unit once placed. He's expensive as hell, but used right he can be a game-changer, so that cost makes sense. Tanuki's cost makes sense too with his new effect.
And there's two that I think should go UP in cost, particularly since they're using the easier-to-get moonstone, and they are Zorigami and Bakezori. I can think of great uses for both of these, and compared to other units with such usefulness they're somewhat cheap.
So, that's my thoughts on that. Feel free to point out arguements against any of this; I always think that the costs of things is one of the hardest things to balance out properly in a game like this, so the more input from different people, the better.