I can't say I'm either disappointed or happy with the Lost season finale. They certainly didn't wrap up all the questions but there's no law out there saying a series finale has to answer every question. A lot of questions can be answered with the blanket umbrella statement: "The island is special and that's just the way it is." For instance, the numbers. In the scheme of the universe, of which the Island seems to play a pivotal role, these numbers are important in a deeper way than humans can understand. At least that's what the writers/producers can say if we really try to drill down on it. But there are far more basic questions that I wanted answered in a finale.
1) The Incident. What happened with the nuclear bomb in the 70s? It's still massively confusing and leads to several sub-questions:
a) Richard said at one point to Sun in season 6 that he "watched them die," referring to all the Losties who presumably would die if a nuclear bomb went off. How come nobody ever questioned him on that statement again? Particularly when all the Losties showed up.
b) When Miles was talking to dead Juliet in episode 1 of Season 1 he said that she said that "It worked." The bomb presumably went off and it all worked. What did she/he mean? How did it work? At the time we all thought they were referring to the sideways reality. But now we know they weren't. So what did work?
2) Time travel. Why did some people go back in time and others didn't? Was it only candidates that went back in time? But then why did Daniel Faraday, Miles, and Charlotte go back in time? As well as Rose and Bernard? Was Rose a candidate?
3) Widmore. What did Widmore really want? I don't really get the entire Charles Widmore thing. He had several contradictory goals.
a) In his original freighter to the island (when Naomi, Miles, Daniel, Charlotte, Frank, etc. came into the cast) he seemed to want several things: to shut down one Dharma station because of its poisonous gases (really? He was obsessed with this one Dharma station that nobody had ever worried about beforehand, including Jacob or Richard?). He also wanted Ben Linus, who was ostensibly the leader of the Others at that time. So it seemed self-serving. And what was he going to do with Linus? Never fully explained.
b) Why did Locke want to kill Naomi and whoever was on the boat? At the time, Locke was one of the good guys (i.e. his motives seemed to be in line with Jacob's) so clearly Locke was trying to protect the island. And yet later, Widmore was fighting the smoke monster. So who was Widmore with? Jacob? The smoke monster? Why were Widmore and the smoke monster such enemies in season 6?
c) Why did Widmore need Desmond? Was he blowing up the island and needed Desmond to do it? We never really found out what Widmore, Zoe, and the whole crew of red-shirts (think "Star Trek red shirts") wanted. And again, if Widmore was working for Jacob, then why did Locke think he was trying to destroy the island with his freighter?
4) Walt. Why'd they need Walt? Presumably the Others were so eager to get Walt because Jacob somehow told them to. Was Richard into kidnapping and experimenting on little kids? Or Dogen? What was the whole purpose of that entire arc? And then why did they no longer want him? (Other than issues outside of the scope of the story, such as the actor getting too big).
5) Eloise. What's Eloise's role in all of this? They all had to visit her to get back to the island. Why? Was she still working for Jacob and getting messages from him? Why did she know that all six had to go back, plus the casket with dead Locke? In that sense, was she working for the smoke monster? And why did all six have to go back anyway? Jacob was so quick with his "piece of chalk" to eliminate Kate because she was a mother. Why was it so specific some times and so arbitrary at others who could remain a candidate and who needed to be back on the island?
6) Mirrors. There's lots of little questions and backstories that we'll never know: what were the mirrors in Jacob's watchtower? What were the numbers? How did the Egyptian statue get there? We can guess and theorize as to all the answers but there's nifty little backstories there and we'll never fully get them.
7) Sequel? Finally, I know the producers have said no more shows or sequels are planned. But what about a sitcom? Richard, the story of a 150 year old man with no known skills who lands in LA and tries to make a life for himself. I volunteer to write the pilot script. He and Sawyer can hang out at bars together and have nothing really to talk about. What are these people (Frank, Kate, Sawyer, Richard, Miles) going to do for the rest of their lives? I want to know!