Don't Try This at Home
As for the Resolution—the kandra mass suicide—well, don't try this at home, kids. This is one of the more discomforting parts of the book, and I don't want to advocate religious extremism in this way. Remember, this is a fantasy book—just like you shouldn't try jumping off your house and using a coin to Push off of, you shouldn't participate in mass-suicide death cults. The kandra had special circumstances, as they were in the process of being taken over by a dark god when they killed themselves.
The thing you can try is what Sazed did, actively using his religion and calling upon a higher power to bring him help. This is one of the core tenets of many religions—that we, as humans, cannot do all things on our own and need the help of others. I'm not exactly sure (again) what I'm trying to say by having Vin be the one who answers and saves Sazed. But, well, in this theology she's now his god, so I guess it all makes sense. Strangely.