I appreciate the reason for Spock's emotive response. But I also quite like that Kirk threw the offer out there to Nero anyway. At least on Kirk's part, it was definitely a maturing of the character.
The real bottom line is that it shows Kirk has got real integrity as a Starfleet officer (or should I say he has the potential
for real integrity as a Starfleet officer?), but the fact that Nero refuses the offer outright pretty much means Kirk and his crew have got the right to take the battle all the way to the endgame. It's the pivotal moment for Kirk, because Nero's refusal confirms his irrationality, and Kirk realizes once and for all that Nero isn't going to stop no matter what. So the Enterprise will just have to do whatever's necessary.
As you can tell I actually like the scene a lot, but it might have been better - more subtle? - if Spock had simply raised a very
quizzical eyebrow at Kirk's offer, rather than speaking out so openly against it. Admittedly it wasn't a moment that called for a particular subtlety.