So while failing to sleep I've been re-watching them. Thoughts ahoy!
In the last ep Coulson said to Skye that he had been keeping something from her and recently (i.e since Ep.11 where he learnt about the secrets kept from him) he had realised he had no right to. Also, in episodes previously Coulson and May have said that they agreed to keep it secret from her, not to tell her. They clearly didn't know the circumstances about all the agents dying, and Skye being the 0-8-4, but they knew something and I'm quite curious as to what. Coulson says in I think episode 2 "An object of unknown origin, like you", but he was clearly surprised to find that she actually WAS one. So I wonder if that was a subtle hint by the writers, an accidental slip or something that they changed/forgot about later in the writing process, or just a passing comment (probably the last one).
Skye's reaction to it all really does make her, as Knick put it just now, very human.
At this rate I am actually expecting May's character history to unfold at some point and be more surprising than all the rest. She was very aggressive to Skye earlier in the series, as well as frequently observing her, only to suddenly support the hunt for information after she found Coulson. The whole Cavalry thing is interesting - initially they say she hates the nickname because she doesn't like the fame and just wants to stay in the background, and she herself is very adamant she doesn't want to do any more fighting. But then she changes her mind (she misses it? if it was so traumatic then that's an intriguing decision) and it is revealed that it was a very dark moment for her, and one that she frequently thinks about. I'm not sure how she connects to Skye if at all, perhaps she's just stubborn.
The Clairvoyant certainly seems to know a lot about everyone, but they state he "knows what the president dreams about" and yet he didn't know anything about Coulson's revival due to Coulson himself having changed, surely if he can actually read anyone on the planet he would simply read the doctors/Fury etc. Agent Hand states that it's odd for so much effort to go into retrieving a single Agent, and we already know that Fury "moved heaven and earth" to bring him back... personally I just assumed it was because Coulson was high up in Shield (He's been there since the first film and was around at every key point) so I was surprised to see him being beneath Hand when they visit the Hub.
Lastly, they really craft the episodes well imo, there are always clues throughout as to where it's going. In the latest one, they mention early on that Donnie "doesn't talk to anyone under 170 IQ" which is a clear lead into Fitz being the one to talk to him. He's using a tablet when they are at the pool, and you can see him and Seth exchange a pretty sinister look just after it freezes, yet Seth says that he doesn't even know him. He clearly isn't a bad guy as he just seemed to want someone to work with, yet he seemed quite pleased with his new found powers. I'd expect to see him again sent out from the Sandbox to work with the team rather than as a villain first, because I would expect it to be hard for him to breakout directly.