First, to those wondering where all the established comic book characters are, this isn't a comic. This universe started when the Marvel Cinematic series began, which is Iron Man 1, so all characters need to be introduced. Also, since Disney doesn't have the rights to all Marvel comic characters, you also have to consider that certain characters might be sitting under the Spider-Man, Fantastic Four, or X-Men brands and can't be used.
On the same point, if you're really expecting them to suddenly introduce all your favorite characters in the first season of a television series, you really don't understand what they are trying to do here.
Second, complaints about this "Centipede" thing. Yeah, there's no way this could be a branch or continuation of AIM, right? Considering the fact that Extremis was a part of that little cocktail they were using, along with Erskine's formula (Hydra connection), and a little Gamma radiation thrown in; sounds exactly like an AIM project to me.
Finally, this show revolves around a small team of agents with a very specific mission. You won't be seeing the Avengers every week, you won't even be seeing Fury, that's not the show. I remember following the Godzilla comic which had SHIELD track the big G as he stomped across the Marvel United States from West to East. Dum Dum Dugan was the agent in charge, but I didn't expect to see the rest of SHIELD's top brass in each issue, and they were chasing Godzilla with the Helicarrier!
Calm down, give them the season to find their legs, and if you're still not happy... wait for DC to pull their shit together, I guess.
William the Bloody Tired of Your Fandom Posturing Redd