There is absolutely no way this happens without Jack. Sayid is the only person who redeems himself in the end by saving, or potentially saving, everyone else.

Why would anyone on the sub trust Jack after he spent the whole episode telling everyone who asked that he was not going away, he now has island fever and wants to stay. 2 minutes after proving that to be a lie by getting on the damn sub, he just tells everyone to trust him as the watch counts down, we can't die? WTF? Can you at least try and explain why when someone asks? Nope. No mention of Richard and him not getting blown up on the Black Rock, just some awesome, "trust me" mumbo jumbo. Hey, trust me, I'm staying on the island...right after I take a backpack given to me by a stranger who I know is not even a real person and take this sub back to civilization. Then I am totally staying on the island. All along I have felt Jack's last name should be Ass. Also, Kate has never done anything but muddy the waters. I am rooting for Hurley. I hope he is happy in the end.

As for Jin leaving, really? I guess I can understand him staying, Sun was real to him in a way his daughter was not yet. I forgive Jin despite thinking Sun needs to tell him to go. Leaving their daughter parentless was a less desirable choice than leaving Sun to die alone. At least I thought that would be how Sun felt.