How about instead of having the Enterprise crashing into Earth, she almost crashes into the moon? It's literally right there. And when power is back, the crew notice that the vengeance, despite being damaged, has enough power to crash somewhere on Earth. The Enterprise, despite being crippled and her weapons gone, tries to intercept the Vengeance and figure out a way of stopping it. As both ships plummet through the atmosphere, the Enterprise tries using it's Tractor Beam to stop the Vengeance, but it doesn't work. The crew than decide to push the engines a little bit to get over the Vengeance and use the tractor beam to push the Vengeance into the coast before it hits the city. This way they stop the ship from crashing into San Francisco and you can still have your chase sequence when Khan escapes the Vengeance into SF. Sure you'll lose the SF crash, but at least this will give the Enterprise a triumphant moment over the Vengeance. I just hate how they had the Vengeance pass by the Enterprise with the crew noticing yet nobody tries to do anything stop her from crashing into SF. They don't even say "We don't have power!" or "Engines are down!". Nothing.