The majority, yes. But I'm of the opinion that the minority still needs to be respected, not dismissed as irrelevant just because their numbers are small. Generally, it's best if you try not to alienate or confuse any segment of your audience. Pandering exclusively to the majority, or what you imagine the majority of your audience to be, is lazy, and it can be self-defeating in that it makes your work inaccessible to people who could otherwise enjoy it.
Which is exactly why I already said that you need to find a balance, a way to provide exposition for new audiences without boring the old audience. It's not about a choice between black-and-white opposites. It's about finding a healthy middle ground.
For instance, when I'm writing a Star Trek novel and I need to recap something from an episode or movie for the benefit of new or forgetful readers, I try to find a way to make it fresh for the rest of the readership, say, by telling the story from a different angle, revealing some part of it that was going on behind the scenes, or filtering it through the viewpoint of a character who has an unusual perspective on it. If nothing else, I try to streamline the exposition as much as possible, to get across just the basic necessary information. I've found there are many ways to avoid an "exposition block" of familiar information.
I used to think that way, but then I realized that real people often do remind each other of events from their pasts, either to jog fading memories or just to share a reminiscence. And I've often heard friends and acquaintances retell the same stories over and over, sometimes when they're addressing other people and I happen to be part of the group, or sometimes because they forgot they'd told me before. I think once or twice I've had someone recap an incident to me because they didn't remember I'd been there when it happened. So there are real-life contexts where people recap their experiences to each other. Of course, if handled wrong in a story, it does come off as artificial, but again, it's not a simplistic all-or-nothing question. There's a lot of nuance, a lot of middle ground in which it can be made to work if you're careful.
I'm always puzzled when people make statements assuming that the writer of a story is trapped by the parameters that exist within the story. The writer creates those parameters in the first place. Given that SHIELD is a security organization, it would be simplicity itself to establish that one or more of the characters weren't cleared to know about Extremis. Or you could simply have one of them not be fully briefed yet -- say, Ward could've not been up to speed on the events of the Mandarin incident because he was out of the country dealing with other crises.
Or maybe Skye could've known. It wasn't a government secret, but a corporate invention. Plus she's a master hacker, so even if it was secret, she could've heard things about it. When Coulson said "Extremis," Skye could've said something like, "You mean that instant-healing process Advanced Idea Mechanics was developing? The one that--" Coulson nods. "Makes people overheat and explode. That's the one." Simplicity itself. Two people comparing notes just to make sure they're on the same page is a natural enough thing, plus you seed the idea of A.I.M. into the series in an organic way.
Maybe the whole point is that these are people outside the normal SHIELD hierarchy, the misfits and eccentrics. Ward is a loose cannon with lousy people skills, May has some dark secret in her past that made her withdraw from field work, Fitz and Simmons are sheltered in their own private little sciencey world, and Skye is an outsider. Rather than making up a team of elites, Coulson has corralled a bunch of strays.
Which, come to think of it, could be seen as following the example of the Avengers. That was also a group of misfits that one wouldn't expect to work well as a team. But Fury thought that bringing them together could generate an effective alchemy, and it worked, and now maybe Coulson's trying a similar experiment on a more mundane level.
I'm not "upset," I just think it could've been handled better here and there. Again, it's not about whether it was done, just how it was done.
The one member of the team who's an outsider to the organization, even mistrusting the organization? The potential dramatic role there seems self-evident to me. Stories are about conflict, but if everyone's part of the same organization, one expects them all to have similar goals and ideals. Skye can be the gadfly, the rogue, the wild card.
To paraphrase something someone said on another board I post on: This isn't a Whedon show, it's a Marvel show that has Whedon working on it. So it's going to be more "corporate," less of his pure vision and more something that he's doing on behalf of others.
Well, Ian de Castaecker is 26, so he at least is in his mid-20s. I can't find out how old Brett Dalton and Elizabeth Henstridge are, though. (Chloe Bennet is 21. Clark Gregg is 51 and Ming-Na Wen is 49, although neither of them looks it.)
