The Lost finale brought hype and a range of expectations. I personally think I let my expectations overwhelm the reasoning that I'm watching a show that can not be concluded neatly. Another reason was that I should have remembered this is a show built more around the characters than the mysteries.
The show provided no clear cut answer on what the island was, but it seems to be a place where evil is being contained by the good that keeps it trapped. Another interesting thing I noticed is that as soon as Jacob passed on his role to Jack, the immortality of Richard and The Man In Black disappeared also.
In the end I believe the show put an emphasis more on human relationships and faith than it did the scientific element in the show. For what reason they chose that route is unknown, but I believe if you look close enough somehow everything is resolved to connect with each other.
Some have suggested the show was mostly about Jack and his journey to finally let go. This seems very true, especially since we fittingly began and ended the show with him. I wonder if they had killed his character like originally planned if the show would have turned out the same at all?
Overall I thought the finale was good after pondering it for a day. Initially I was disappointed because people were suggesting they died when the plane first crashed. After I found out that ABC badly put together the clips of the plane wreckage at the end I felt better. I'm sure some things could have been explained better, but in the end it was concluded as it was intended to be.