Someone mentioned Smallville at one point. I think that show succeeded (I watched it twice over the years) because it had a lot of comedy elements, didn't take itself very seriously. And when it eventually did in the latter seasons, it had all the groundwork built up for it so the viewer wouldn't be wondering what the fuck is going on.
Because Gotham, from that trailer, doesn't seem all that relaxing. And without heroes/villains, it's just a regular procedural detective series.