and I have to say, this is not specific to LOST. There were many shows that just didn't survive that strike, because the 'kids' were now too old looking, because in that time, what people wanted had changed.
LOST was always magical, right? it had suspense and mystery. There was a freaking polar bear on a tropical islands and everyone was on board with that until....they forgot that's what made LOST so awesome.
There was never going to be a 'rational' explanation of why the island was the way it was, there is no reason for the time jumping. That was always okay with me.
I love the finale. I love that everyone winds up where and with whom they had the deepest connection. I love that they ALL had to be together before the next step. For me, it's one of the greatest finales ever.