the ending they gave negates alot of moments/episodes/scenes that we were led to believe would be pretty important, for instance, MIB putting desmond in a well and telling sayid to kill him. doesn't make much sense since he needed desmond to get off the island
He didn't need Desmond to get off the island. He needed the candidates dead to get off the island. He tried by blowing them up in the submarine, but when that failed, he realized that with Desmond still alive, he could use him to destroy the island, which would inadvertently kill off the Candidates, again giving him the opportunity to leave the island. He can't kill them himself, just like he couldn't kill Jacob himself. He needs to accomplish these things through pawns. The bomb in the sub would not have gone off had Sawyer not pulled the wires, just HIMSELF activating the bomb and killing the others.
I found how amazing and far reaching some of the main themes of the show were. I just realized that Jack started off as the man of science and by the end of the show, became the man of faith. Likewise, WE, the audience, began the show as people of science, and by the end, as the creators intended I believe, to transcend into people of faith. That's why so much of the show was based on the mythology of the island, why so many of the QUESTIONS
were indeed ANSWERED, but not in a scientific way that Jack wanted initially, but rather through mythology - and, like Jack, you needed to have faith in it to accept them as the answers.
The show also reflected heavily on, just life itself. Some of our greatest mysteries cannot be answered through Science. And when we try, we get vague theories, that are eternally complex and only justified by equations and beliefs in formulas - not through actual witnessing and believing (Big Bang Theory comes to mind). And what CAN actually be the answers to life's greatest questions? Well, faith again. And you need to believe, to be content with the answers.
The parallels to our lives. The themes that expand and encompass so much. I thought the show was beautifully done.