Really, the weirdest thing to me about those sacred giants, in this game, was that... none of the sacred giant people really did anything with them (from what I could see, anyway). Boksi was the most aggressive sacred user I noticed, and they staled like 1/10th of their turns. Don't think ever really attacked anyone except Al, either. EA got jumped by pigeons, BFEL and Iwa just seemed to somehow die off while playing in the water or somethin', it was ruddy weird. I was seriously expecting giants to come stomping over the everything for probably the first thirty turns or so, but it never seemed to manifest.
Though re: Giants and costing, while it'd probably be (much) easier to bump their price/add penalties, what I'd probably like to see more is doing something to the little people. Make it so tiny folk in a world of sacred giants actually have something that can gold-for-gold match the blighters. Maybe do something really silly and have the generation process check (probably near the end of the process) for size>own!sacred and dole out a point or ten of giant killer for every size category they're lacking (maybe multiplied by the percentage of genned nations that have a giant sacred?), or something to similar effect. A post-gen check for % of genned nations that have sacred giants, and then adding more stuff to everyone else's sacreds based on how prevalent they are, that kind of thing. Think I said it somewhere else, it wasn't really the giants or the formorians, it was just how many people had the things that was the major problem -- didn't have that kind of meta balance the base game has, where a giant nation is more or less all alone.