The show certainly has... flaws. Mostly one is that I'm not sure what's going to sustain this show (story wise) over the course of several seasons. Hell, even one season. Aside from some threads here and there the episodes we've gotten have been fairly, well, episodic. And, worst of all, we've got some pretty bland and uninteresting characters. Aside from Coulson who else there really to root for? Blandy McSquarejaw? Cute Nerdy Chick Trope 27B-A? The Technoblather Twins? There's not a lot to grab onto here.
As bad as the first few episodes of TNG were at the very least you had an interesting range of characters all with personalities coming together in an interesting group dynamic. Hell, we have that with the first episode of "Firefly" plus the establishment of the type of universe we're in and maybe *some* idea of where the show is going and focusing on.
I'm sticking with SHIELD but, really, only out of some sense of loyalty to the MCU but, right now, it's not a show I'm raving about or would itch to get people to watch.
Watching the first episode of "The Walking Dead" got me hooked and I watched the next episode right away! Same with "Firefly" or, hell, most other shows I watch(ed) and love.
AoS, so far, nothing has really happened to lock me on. It's been fairly bland and generic so far and only has the MCU to carry it. It really needs more than that and, maybe, stop playing so safe.