That's an unwise assumption. The whole reason you make multimedia franchises in the first place is because each new medium brings you a different audience. Sure, a large percentage of this show's viewers will be people who've seen the movies, but if you're moving something to a new medium, you want to make it accessible to people who haven't seen its previous incarnations as well. Heck, even within a single medium, one of the basic rules of series writing is to assume that every installment will be somebody's first, and thus to make it comprehensible on its own. You don't want to overdo the exposition to make it boring to those who are familiar with it, sure, but there is a comfortable middle ground, a way to balance both audiences' needs. As I said, it's not that it was mentioned, it's how. I felt those mentions worked better. Simmons listed the serum, gamma radiation, and one other thing and said they were "every known source of superpowers," so that explains what they are. Coulson just said "Extremis. It's new." That's not enough by itself. I'm not opposed to mentioning Extremis, I just think it could've been handled better. I find the three female leads to be very easy to tell apart. Ming-Na Wen is a famous face in her own right, and she's older than the others as well as being the only clearly Asian cast member (Chloe Bennet is half-Chinese but doesn't really look it). And Elizabeth Henstridge's hair is a lighter, more honey-brown shade that the others' and a lot straighter than Bennet's, plus she has an English accent.