Okay so, initially I was on the fence but more with the crowd of "Hey wait, 'this' particular thing was not answered" etc and et al.
But now, the more I come to think of it... People have been comparing LOST to an Agatha Christie saying it's like Agatha has written a story and completely left out the bit where the crime/murder is solved.
If people would look at this more along the lines of a Stephen King book then maybe, just maybe you could all coexist in your opinions... I mean let's face it, taking two brilliant examples in the "The Dark Tower" series and also "Under The Dome".
Both books were stories which dragged us into complicated relationships with all characters both good and bad and at the same time both books had completely weird, scientific, religious, mysterious aspects to them; but in the end of both these (the TDT saga and UTD alike) - A LOT of those mystery's went unsolved a lot of them went left unanswered and that is the right of a good author/writer in general.
Albeit that said I still agree that they shouldn't have made certain aspects "focal points" such as the Island and its mysterious harnessed powers or Walt's "Special"-ness. But seriously think of it like looking at a series of books in a collection such as The Dark Tower; finally closing that last page and still thinking "But what....[Enter rest here]??"
Both were able to coexist and both did... To be honest, not even the character development was resolved because I personally still don't know how a few of the characters actually died or what happened throughout their lives, beforehand. - All I know is LOST took us through a journey from beginning to end. I kind of look at it like an awesome cake which was eaten from the inside out...