About the Prometheus thing... Guys, I think Boney's warning may have been about the reaction that OTHER gods would have to this, rather than to Ranald specifically.
I think this was Boney saying: "What're the possible effects of Mathilde doing the 'Prepare a secure container to store the crystal in, with room for many more to come.' thing with not just Ranald but other Gods -- whom we don't have a close relationship to -- too? Weelll... Take a look at the myth of Prometheus for possible examples."
So, no, I don't think Ranald would necessarily smite us for this.
I do think, however, that we would be holding knowledge and means -- or researching to gain the knowledge and means -- for which other gods would or might smite us for. And like, sure, if it was just Gork and Mork and Hashut and Stromfels and Khaine we were going to target? Fine, okay. Risky as hell, but not unethical, due to targeting enemies and all that, right?
But our targets of potential possible research would also include all the other gods too. And we would be on far more uncertain and unknown (and possibly unknowable, since we wouldn't be able to put in the time and effort to get to know every other god as personally and thoroughly as we did Ranald) grounds there. And the temptation would be there all the while. The temptation of knowing better, or of "Well this is necessary" or "This is for the greater good" or "For science!"
That's another major reason I don't want to do Truth, and want to do Faith instead. Because I don't want to risk entering into a conflict of interests of Mathilde versus Gods. And instead, I'd rather stick with the guy we have a great relationship with instead.