I like "Agents Of Shield" on it's own merits, but I feel it fails given that it's big selling point is supposed to be the Marvel Universe, and really for the most part it's not even obvious that it's supposed to exist in that universe. I am thinking that maybe they wanted to take this show slow, and have the super-agency develop into something more like the comics, but if that's the case they have misjudged the audience.
I'll also be frank in saying that I sort of suspected this might happen for reasons of budget, simply put a TV show doesn't have that much money to sink into itself, and that is one of the big reasons why they focus so much on drama as opposed to big FX when doing science fiction. Many episodes of say Star Trek involving very little except a bunch of people sitting around and gabbing for the most part. I vaguely remember an explanation as to why they didn't do more as far as space battles and such as to the cost of doing the FX for even a single phaser blast, never mind the stunt involved in having someone shot/fall down, which is one of the reasons why people tended miss a lot in Star Trek, and the crew tended to take a beating, because it was easier to put faux burn marks on someone's shirt than it was to try and modify a lot of the alien costumes and such, some of which were apparently pretty stiff which made falling down tricky to say the least.... which is neither here nor there really, but I'd imagine half the problem with SHIELD is
that they just don't have the budget for super heroics, especially to the quality standards people would expect from the movies. Cop/Spy shows and sitcoms are relatively cheap to make, since it's easier to do gunfights with prop guns on the cheap than it is to say have people throwing lightning bolts around, or being thrown through walls, and similar things. Just the FX to let the shield agents blaze away with energy weapons would probably be too much.
It's noteworthy that Joss Whedon managed to do a lot with a fantasy TV show, namely Buffy, but in part that worked because it was almost all fist fighting when you get down to it, and he was able to make all the cheez part of the charm. That level of FX and makeup wouldn't work for SHIELD though because of the standards people have from movies that cost millions upon millions of dollars and only had to fill 2 hours or so of footage, where SHIELD has to fill 20+ hours (I'm guessing 21 or 22 episodes for the season, but I'm not sure) with a tiny fraction of the budget.
I am kind of interested to see how Netflix and it's super hero shows turn out, I think they chose a wiser path in wanting to work with low-end heroes that don't have much in the way of powers and neither do their usual rogues gallery. Cage, Iron Fist, etc... all tend to ultimately punch it out with bad guys that are usually just thugs in costumes, or have "heightened physical abilities", meaning they can more or less do the "Buffy" thing, not being expected to play on the level of something like SHIELD where half the idea is supposed to be a bunch of agents with super technology throwing flashier super villains into the slammer somewhere in the shadows of various comics, explaining why the world doesn't fall apart due to heroes not being able to be everywhere at once, and occasionally neeing to get actual super heroes to lend a hand when things go even more pear shaped than usual.... the show was basically just too ambitious for a TV budget.
I'll also say again, as much as it cheezes people off, doing the "Ultimate" Nick Fury for political correctness reasons was a mistake. One of the big things behind SHIELD was that they had Nick Fury with them who pretty much covers the same ground as Captain America, minus the angst, and replacing a variety of weapons, android duplicates (LMDs), and things for the shield gimmick. He's another WW II hero with decades of experience and who pretty much benefited from the same kind of enhancement as Captain America. He's older due to being constantly active, but had his aging slowed so he's still acting like he's in his prime pretty much. As cool and PC as Samuel L. Jackson was, using him means he can't be a regular member of the cast, and I feel that's kind of limiting their options, not to mention that if they used him, this version pretty much doesn't have any powers, so it makes it harder to justify him occasionally going toe to toe with villains. Part of the point was that if Cap could pull something off, Nick could probably do it too. Shield also used a number of super agents (which I thought the show was going to be more about) including characters like Malice (Nick's daughter), Talltale (I think that was his name, basically the more he lies about himself the stronger he gets as he does it), and some others. At the end of the day I think half the problem is that if this group of shield agents we're looking at could take down super villains, they couldn't be considered very super. Shades of the old joke about "in evaluating how much of a threat a comic character is, ask youself are his powers better than simply carrying a gun...", surely there are comic characters this version of SHIELD could handle, but most of those are ones we tend to make fun of or see as knock down villains, not the guys we want to actually see.
We'll see where it goes, hopefully I'll be pleasantly surprised in the long run. Despite my neighsaying I plan to keep watching and find out. I stick with it largely because if this winds up not getting a lot better on average it will be the first time Joss Whedon really disappointed me that I can think of.