I'd weight the "percent-me" of the change. Me-but-without-LW-rationality is maybe 90-95% me. Me-without-any-interesting-in-critical-thinking-at-all is like 75% me. Some form of silliness and self-expression is about 35% of my personality-makeup. I think I value general inclinations more than specific knowledge/ideas, since those change more over time.
So a 10% chance of me surviving-sans-silliness-and-art-inclination is basically like a 6.5% chance of surviving.'
I was reading about the effectiveness of bicycle helmet laws (here) and wondered how worthwhile it is to save your life at the expense of some aspect key to your current identity (Note that the paper linked doesn't say that this is the situation; this was just a tangential thought).
Let's say that I perform some activity that carries a 10% chance that I will die but otherwise carries no risk of injury. There is some piece of safety gear that I can wear that cuts that risk in half, but for some reason adds a 10% chance that I will be permanently brain damaged such that I will not be "me" as I understand it now. Should I rate this as 15% fatal with the safety gear or is there some other way that this should be evaluated?