Overall I liked The End. It seems to have split into love and hate camps. I sort of lean toward the love camp. However, The End did have some flaws.
Flaws:
The Flash Sideways- I understand its intention but it seemed to be slightly dissapointing. I really thought that Desmond was going to take the flash sideways characters and reunite them with the surviving island characters. I don't really know how this would work. I almost see a massive moment of reuniting in Tunisia. Maybe Desmond turns the wheel wakes up sees the Ajira plane crash/land behind him. Also, Penny shows up with Walt and co. Probably due to a note from Charles Widmore. On the plane they feel sad that their friends are dead etc. Maybe through some time skip the FS Desmond and every FS character and co are brought to Tunisia. The FS Sidways character live on after their dead. The FS Sidways characters who have an alive island counterpart disappear and merge with the on island counterpart retaining their memories. Maybe this would work better.
Another ending of like M.I.B. invades the FS sideways reality dies and Jack saves the island reality. Which was the true reality. He dies through a trap orchestrated through Jacob and carried out through Jack. Jack somehow switches the realities when M.I.B. leaves and kills him through some messed up version of course correction.
Another ending would be traveling through time to 2004 and have Desmond push the button preventing the crash. Which erases M.I.B. winning and making the Flash Sidways somehow the true reality. The island sinks in the past, present and future. M.I.B. and Jacob die with the sinking of the island. Although the island is sunk the source is still alive. This is done through the whole Jack/Jacob scenario. I don't know coming up with these scenarios means it could've been so much better. However, The End was still great though.
Another Flaw was the whole Claire and Kate scene. Isn't it irritating that Claire never mentioned Charlie's death. I think that might make her feel like she lost everything leading to her personality change etc. Nevertheless it should've been more emotional in my opinion.
David- David feels useless. Yes I understand the theories on why he existed. Most likely to solve Jack's daddy issues. However, it did not make any sense. The opening scene of the clouds makes sense for the alternate reality. The Hint was right their purgatory! Nevertheless, the sideways world felt a little like a cop out. Its just my opinion though.
Frank, Miles, and Richard not being used enough. Okay Frank had his moments such as the whole I'm busy, throwing the walkie and Ben stating that they were making progress was brillian. Miles duct tape line was great to. Richard was underused. Overall I thought that he deserved more screentime and was one of the most fascinating characters of the show. I also thought he should've died, saw his dead wife and then reunited. Other issues were the whole Sun and the whole not talking English thing. Also, the zombie Sayid scenario wasn't really working. What I noticed was a bunch of characters not being used properly until they got to a certain event. Like the writers knew what to do with them at that seen but not knowing what to do with them before that. Frank was underused until the plane. Miles not really used. I thought he was the one who was going to kill M.I.B. Sun, Jin and Sayid not used until a death scene. Richard not really used after Ab Aeterno. Ben was deconstructed and not really had his moment until What They Died For. Finally, making Desmond look like a fool in the end gave me a bad taste in my mouth. I felt like he knew everything and having him misguided felt like a blow. Desmond not reuniting with his wife felt like a wasted scene.
Okay so what now. Ben and Hurley rule the island. Probably can interpret closure for everyone else. Hopefully Damon and Carlton reveal their orginal plans for the mysteries and what they meant. If they do this I feel satsified. People who wanted answers were disappointed. People who wanted conclusions with characters were rewarded. In the end I felt like I wanted both. I only got one. Even the answers for the season felt kind've weird. The whole Black Rock slams into the statue knocking it over. The Black Rock goes inland. It was like how can we nail two mysteries at once. The whispers not so great either. Across The Sea not really great either although I understand what it was trying to do. Maybe they should've have answered any mysteries at all. Isn't that the point of Lost? Debate. Answering half meant okay what about the other half! Its like the writers can't win either way so I'll cut them some slack.
As for the end I just give The End a 7/10 and call it a day. Well that's it Lost is over. The End will grow on me like Across The Sea. I'll accept it at some point. Just probably later instead of now.