I enjoyed that little sneak peek as well and was disappointed when it ended. It was a little rough around the edges, in my opinion, but so was Clone Wars when it first started and I see far, far more potential in Rebels than I did Clone Wars when I first started it. I like that they're acting like true rebels and are not the Rebels yet so they're doing small stuff and stealing from the Empire, they look they're also going to do a good job at establishing how repressive the Empire truly was.
I think what I liked the most were all of the old sound effects, the blasters, the TIEs, the sound of the speeder or swoop bikes, it really brought me back to the OT and made me realize just how much I actually missed those old sound effects. I can't wait to hear those Stormtroopers talk, that's really going to bring things back, I just hope they don't make them all sound like the Clonetroopers.
The one thing that I didn't quite like was the beginning with Ezra(?), that was just a little too Aladdin like for me. As soon as he started jumping up to the top of the buildings I kept on expecting to hear him start singing "One Jump Ahead". It didn't help that the character design sort of resembled Aladdin too, but I did kind of forget about that once the action started.