here's what I think I know about the starstone:
1. the Test is mysterious and highly personal.
2. the stone was called down from the heavens by aboleth to destroy Azlant.
3. it elevated Aroden to godhood.
4. the Starstone seems to have an intelligence of its own, but its an alien way of looking at reality.
5. the Starstone seems to have incredible powers - it created the island of kortos after all.
1. the starstone has an agenda.
2. the starstone was called down by ABOLETH! they like to dabble in slimy horror magic. could the stone be tainted by the dark tapestry?
3. there are other means of achieving divinity...the starstone is merely one means among several. why is the starstone method so well known? you would think that something like that would be a Big Secret.
there's a lot of unknowns regarding that god rock. given a choice between lichdom and taking the Test of the Starstone, I think I'd go with lichdom. at least you know what you're dealing with...I just don't trust anything connected to the aboleth.
Well, considering that Iomadae is Lawful Good, and has been for several thousand years AFTER her ascension with the test, I doubt it is corrupting her. But the rest of the suppositions are interesting. And Lichdom is only good if your character doesn't worship a God/Goddess that basically hates undeath. And I agree about the vast sea of unknown about it, but I think that's a good thing - it leaves it open for interpretation. Also, I think the best way to keep a Big Secret is right under everyone's nose. :)