Basically how it boils down

To be honest I consider season five to be the low point, or more accurately, the falling action. Season 4 finale was the climax of the series; all loose ends were tied up. Season 5 was the cooling down before the end, we knew where this was headed right off the bat in season 5, though we didn't know the cause until the very last moments of mid-season finale. I don't think it was bad, just the least interesting. The last season was about wrapping up the story, it did it's job well. Maybe it's just me but I think they kinda jumped the shark with the of season 4. They wrote themselves into a corner simply by making something soo freaking good that they couldn't surpass that bar they set themselves.