To that en, Kudos to Meyer for wanting to leave it more open-ended.
Well, Meyer said he did not add the torpedo on Genesis. That was Bennett.
As for life from death, they also said it destroys the original life to be replaced by new different life. But you make a point I never associated with Spock death in that movie. I never took it as a way out. And I was too young to know Nimmoy was rumored to want out.
You're right, it was Bennett. My mistake. Meyer was the one who wanted it more definite.
The very earliest treatments of the TWOK didn't even include Spock, because Bennett was so sure Nimoy wasn't coming back. Offering him a great death scene to kill the character off intrigued Nimoy and got him to come back.
There are two main reasons for making the death scene less certain. The first was negative audience feedback to the more definitively done version. The second was it's said Nimoy had a better time than he thought he'd have and came to realize this would proably not be the last Trek movie. (I'm not sure how promises to direct Trek movies worked into the equation.)
Well before the release of the movie, the "secret" of Spock's death was thoroughly spoiled all over the place, even in the pre-Internet era. The media began hedging on his death being irrevocable.
(If I'm wrong about any of this, someone will be along shortly to politely correct me.