Nero's motivations certainly qualify. 25 years of hatred for the man who tried to save his planet... okay, if he's a madman, I could maybe buy that. But I feel at some point one of his crew would get fed up with the obsession, realize the ramifications of destroying entire worlds, or be worried about mucking up his own timeline that he'd put a distruptor up to the back of Nero's head and pull the trigger.
I found a good respose to that in another thread.
Nero is a passionate, angry, irrational, hate filled, half mad (or fully mad) man.
He has seen his family, his entire planet destroyed because Romulan and Vulcan politicians would not act and do what's necessary. Because they let stupid pride and prejudice blind them.
He placed his trust in Spock and his promises and Spock did not deliver. All he ended up offering is patience and more words when swift action was needed.
He wasted valuable time instead of maybe even helping Nero steal by force the technology and save Romulus at all costs.
He was thrown back in time unwillingly and spent a decade in a Klingon prison.
He has a super advanced powerful ship in his hands that destroys Klingon armadas. He does not believe he can lose.
He has centuries to save Romulus in this timeline and a burning desire for revenge right now.
I don't see how anyone can expect such a man to do what we consider the right course of action sitting safely behind our keyboards.
I could see that - if it were included in the film. Unfortunately we don't get more information than 'Spock was too slow.' And even if, what about the crew that followed Nero around for 25 years?
Eh, Kirk running into Spock Prime in some grungy spaceship just doesn't have the magic and mystery of an ice cave on an alien planet (and I'm sure the writers also wanted a better backdrop for the mind meld sequence). And while Spock Prime watching the destruction of Vulcan from this planet may not be completely plausible, it still seems more visually poetic and elegant than him watching it while floating in space in a spacesuit. All the special effects and hardware would get in the way of the emotion of the moment.
I agree, but sometimes poetic license can be taken too far. Spock maybe/maybe not seeing Vulcan get destroyed is one of those times - did he or did he not see Vulcan go kablooie? With his mind or with his eyes? There's no way to tell from the movie itself. To be honest, Spock Prime's character reminded me of 'Basil Exposition' from the Austin Powers flicks - there to explain the plot and not much else.
Besides, it would still strike me as a massive coincidence that Spock deposits Kirk on the ONE ship in the quadrant that happens to be carrying Spock Prime and Scotty.
You're right, of course, it would be, but less so than what we got. Vulcan's distress call would bring ships in the near sectors in for help, which would give a
reason for all these people to be in the same place. There's no reason for Spock Prime to be on that ice planet; there's no reason for Kirk to be on that ice planet. Well, no good ones anyway.

Scotty responding to Vulcan's distress call with his little salvage ship and finding a floating Spock Prime in distress would be a good way to unite them. And Spock Jr. hailing Scotty's ship and asking if he has room for another passenger would be better than chucking Kirk out in the snow.
As for watching the destruction of Vulcan in a spacesuit... I think that could be handled very well to be emotional. Imagine, floating derelict in space, watching your homeworld implode, and there's nothing you can do about it, your screams echoing in your own helmet... then left to slowly asphixiate.