There are a few reasons.
1. FranchisitisThis is the word I think of when I think of Batman post Tim Burton, Spider-Man 3 and Amazing Spider-Man 2, any mainstream comic book series since "The Death of Superman", any soap opera.
It can also be thought of as sequelitis or just a fucking cash grab. Anytime a villain survives a battle in a movie when there isn't a really good fucking reason, I start to feel a case of any of these diseases coming on. In fact, with each new Marvel Cinematic Universe movie since the Avengers, I've been pretty concerned. Loki? Responsible for billions of dollars in property damage and countless human lives? On house arrest. OK. That's lucid.
It's why in comic books you can't ever say anyone is dead even if they are dead. Seriously Spider-Man? Clone Gwen Stacy? What the fuck?
And Defiance has always suffered from this as it's been tied to some dumb game. The show's actors and creators touting it as a great feature where characters go to and from the TV show to the game.
So this is just some world we're watching and there's no real point even if there are the occasional plot points. Soap opera.
And a cash grab more than it is a fan service.
2. Cool kid syndromeI don't have a problem with dark. I really don't. I devoured "Game of Thrones" before losing faith in Martin as a writer and creator.
I don't have a problem with darkness. But darkness for darkness's sake? I get it, the world sucks. Move the fuck on. Fallout at least is humorous. The Book of Eli was riveting. Are any of the characters here at all sympathetic? They all have some dark skeleton that you'd think might be mitigable or understandable or something, but in the end they're really just douchebags.
They're written as douchebags because douchebags are "cool", but not really. Badasses can be cool, but they have to actively be badasses to be cool. They can't just phone it in during an episode or you have nothing other than douchebags running around performing douchebaggery.
Even characters that you want to like are annoying.
Battlestar Galactica almost lost me as a viewer when there was a shift in power and they settled on that dumbass planet for a year or more or whatever. This entire show feels like being stuck on that dumbass planet.
I've checked out. I will continue to watch Dominion, because angels, demons and the apocalypse are some krytonitey shit for this particular consumer (could you tell? Zero Angel. Apocalypse Designs), but I won't watch Defiance anymore.
I've begun to lose faith in Marvel cinematic universe even though Cap 2 was the best Marvel film I've ever seen (entirely because of fears of franchisitis). I've lost faith in Amazing Spider-Man. I've regularly lost faith in a variety of television programs because of this (Inu-yasha, Heroes, Smallville, Doctor Who, to name a few).
I'm just so sick of getting my hopes dashed. I'm not going to tolerate some show that doesn't even inspire me to the same emotional heights as good television and movies do.
The pilot was pretty good. After saying all of that above, if the show had been just a little less drawn out (which is yet another symptom of franchisitis. Inu-Yasha made up an entire season of filler episodes while they waited for the manga to catch up. Can you imagine Game of Thrones TV doing this? Heroes started sucking when practically nothing happened for entire episodes. ) then it may have held my attention. At least I wouldn't have felt like my time's been wasted.
Another symptom of franchisitis by the way? Multiple part seasons. Season 1 Part 1. Season 1 Part 2. Blah blah blah. Fuck you Stargate Universe, Doctor Who and Battlestar Galactica. And I loved those shows.