Much,
much better Episode 2. Nice to have the characters interacting with each other so much, and the banter seemed much improved for my money. Some very nice action scenes, and just overall the episode seemed a lot more focused and cohesive with its characters. Ward's a lot more likeable, I'm intrigued with how they'll handle Skye's story, Coulson's Tahiti experience should be an interesting mystery, Melinda May is a nice slow-burning mystery.
Fury's appearance made me grin. Sure it didn't add much, but it was a lot of fun. Besides, why not check in on his... third-hand (?) man who's just recently come back from "Tahiti?" I didn't read him as being truly angry, just more flabbergasted and venting some steam.
I don't think F & S are interchangeable. Fitz is the more neurotic, sensitive, timid one while Simmons is more upbeat and reassuring. As we heard here, she's the one who prodded him to go into the field, while his preference would've been to stay in the lab. And she was friendly and welcoming to Skye while he was rolling his eyes and barely seemed to tolerate her. Aside from both being technobabble-spewing science nerds, they're pretty much polar opposites. Which is no doubt why they make a good team -- they complement each other.
Huh, you read Fitz' interactions when Skye arrives on the bus completely opposite from me. I didn't see him as barely tolerating her, but as being flustered and maybe attracted to her.
I gotta say, am I the only one that
loves FitzSimmons? They remind me of a somewhat more neurotic Ken and Gabi from
Mass Effect 2/3. (Actually, the whole setup feels very RPG-ish to some extent - The Bus is Normandy, Coulsen's Shep, May's a blend of Joker and Wrex, etc.)
Sure, they haven't actually done a whole lot yet and I can see how they'd come across as obnoxious, but they just make me grin.

I'll be annoyed if they kill one of them for tEh drama, but with this being a Whedon show I expect one of them - probably Fitz - to bite it down the line. And I'm sure they'll make it work really well and be a good tearjerker that leads to some really good stories, but nonetheless.
Speaking of deaths, what if the real twist about Coulsen is that he's actually aware of his nature (assuming that there's something there - LMD/clone/whatever) and he's mostly worked through the emotional baggage of it, somewhat explaining his notorious sentimentality? The big reveal will just be for the other characters (and the audience of course), but Coulsen will be aware.