Coulson, as a character, shouldn't be shouldering the majority of the arc based story progression. It detracts from the ability of that character to be the wildcard element that could pull victory out of a hat, which is part of what made him an interesting character to begin with. I don't dislike the show but it has just enough glaring flaws to be, for me at least, a pain to watch. I'll still watch it as I am interested to see if it can pull out of the nose dive that I see it in at the moment.
Most of the characters seem to be trying to do double duty in terms of what their archetypes are, this is causing conflict. One of the most obvious places you can see this is in the Fitz-Simmons character interplay. Even totally discounting how desperate the writers seem to be to get some kind of fandom shipping going between those two characters there is a glaring problem in the way that, thus far, they've been scripted for me. Fitz is far more potentially interesting without Simmons, whereas Simmons is entirely reliant on other characters (not including Fitz) to be of any interest. I've said it before, if Simmons had died/been presumed dead it'd be a much more interesting show right now. Fitz is a character trapped between who the world expects him to be and who he really is. He is desperately trying to be the former, the helpful and highly intelligent support officer, but the few glimpses we've seen of the latter, the vaguely authoritarian genius with no time for other peoples mistakes, has been interesting to say the least.
Other examples of the double duty are Ward, spending equal time in grizzled bad-ass and earnest recruit, and Skye, who can't seem to decide whether she'll believe in herself and become the princess she really was all the time or simply focus on actually achieving her personal goals.