Gotham's lead character, Jim Gordon, is played well enough by Ben McKenzie. His generic appearance and "one cop against the world" mentality could be tired and boring, but McKenzie keeps it interesting by bringing intelligence to the character while he observes the world and learns the game in the first half of the episode. The plot throws that intelligence out the window when Gordon confronts Mooney, and though Gordon's brooding is believable, it's not much fun to watch. Still, Gordon chooses to fake killing Cobblepot rather than insisting to stand for his morals. A Gordon that plays the game to break the system will be much more interesting than an uncompromising hero, anyway.
One other character that stood out to me was Renee Montoya (Victoria Cartagena), an officer in the Major Crimes Unit (which Gordon runs early in the Dark Knight trilogy). Montoya was a favorite side character of mine from the comics, and I'm glad that Cartagena is a series regular. The fact that she is working to save the city from the corrupt police while thinking Gordon is just another one of "them" is an exciting concept. There are allusions to her having an unhappy past with Gordon's fiancé, Barbara, and it looks like that might be a romantic history. I love the way Cartagena plays Montoya and her focus on the passion and anger of the character.
One other thing the show has going for it is its sense of humor. The show skirts close to being too grim, so the ability for the character to make jokes is crucial. A number of the lines earn a chuckle, for instance when one of Mooney's henchmen asks Gordon "How you liking Gotham?" in a far too casual way given the circumstances (even the random henchmen are played well). When Bullock tries to get Captain Sarah Essen (yes, the Essen from the comics) to reassign Gordon, the new detective jokes, "You'll get used to me."
Gotham depends on these little things. The cast is the best thing the show has going for it, and that can count for a lot, but the jokes and unique visuals are crucial, too. Equally important is the show's ability to tell a story supported by Batman's established characters and themes, rather than a story centered around them.
In fact, the story is motivated by the murder of Bruce Wayne's parents, which is played out as an assassination in this interpretation of the events. Still, while visiting the origins of the Dark Knight is an interesting side plot, rather than the focus for the show.
Bottom Line: Overall, Batman-without-Batman works, but it is so close to failing that each episode will need to at least keep up with the pilot or, ideally, improve. The show has plenty of room for improvement, but there is definitely a basis here that can work, and I'm more excited for the next episode than I was for the premiere.
Recommendation: A definite watch for Batman fans. Others may be turned off by the weak points, but the Gotham pilot is worth checking out for what the series might become.