Let me just say that even LOST's worst episodes (and this was clearly not their worst) are far better than just about everything else on TV. LOST is the top show on "the tube" right now, and there is no intelligent debate that can be brought up against that point. With all that in consideration, this was not a strong hour of the show.
While the acting was decent, and the ending was an okay cliffhanger (poor by LOST standards though) you could've watched that last five minutes of the show and not missed a single thing. Where are Desmond and Sayid? Are they okay? What's going on with Locke and Ben? This was such an isolated episode, and it was hard to feel compassion when Jack, Kate and Juliet have been pushed out of the spotlight in recent weeks. Not to mention Jack's appendix was not exactly the most hyped storyline in the world.
Development. Building. These are not just terms that are used by construction workers. The job of the writer is to develop an entertaining story that builds toward a climatic moment. There was no true emotion regarding Jack's surgery. Did anyone think he was going to actually die?
Miles and Sawyer are developing an interesting bond and should be nice to see what this builds toward. Still though, it's hard to get into anything Claire does on the show, and I could care less where she is right now. It's not just that the actress portraying her fails to take over the screen it's just that there are more important things on the viewers mind. We're no more anticipated toward next week's episode now than we would be had she not disappeared.