After season 4, which was just awesome television (Lithgow was the creepiest bad guy, loved it) I didn't have the highest expectations for season 5. I mean that was hard to follow. I thought they pulled off 5 prettty good. They did start some interesting story arcs that just kind of died, like the machete killers and Quinn vs. Dexter using the trinity killer's family. I thought those had more potential, but I still like where it ended up. I thought the finale was good, tied off the loose ends as usual, although pretty abruptly and pretty fake with some of them, but I still liked it. I would love for them to end with some kind of cliff-hanger, but that is not their M.O. It would have helped this season though without closing off so much so falsely.
I am with others here that I cannot see how long they can continue this in miami. How many freaks and serial killers can a single city have anyway, even Miami? Move it to LA and it can continue idefinitely. To go much beyond where they are now they will have to really beef up the writing and get something fresh. I don't want the series to end anytime soon, but I don't want to see it fade out in crappy writing, getting drawn out too long. Hopefully they can come up with 2 or 3 more solid seasons before outing Dexter and ending it all in some glorious blood bath.