The opening act for Rebels is a little clunky, but it finds its feet remarkably quickly and, once the core cast have all been introduced, the show evolves into something genuinely enjoyable. I'm not completely sold on the animation style (I wish we'd gotten more of the Clone Wars style, to be honest), but they quit it with the weird zoom cuts and overly elongated mouths early enough that I've largely gotten used to it at this point. And, of course, the plot is distinctly child-focused, which is fine but don't go expecting any real depth or nuance to proceedings. But, still, the characters are interesting and it's fun to explore the Outer Rim at the start of the Empire.
The inclusion of both a Jedi that escaped Order 66 and a young force-sensitive makes for some interesting dissection of the Jedi Order, and I've been interested to see how Kanan is applying his teachings. He certainly seems to care a lot less about the whole "purge yourself of attachment" which feels right for a post-Jedi world. At the same time, though, Ezra is remarkably powerful incredibly quickly. I don't think they've quite hit Dragonball levels of overachieving, and they do show him mess up from time to time, but for someone with less than a year's training, he is probably a bit too capable.
I also hope that Zeb gets a bit more back story and maturity. He's hinted at being some fancy senior military leader, but he acts like a child. Plus, the whole "Empire committed a genocide against my people" bit is an area with a lot of complexity to explore. I wouldn't have expected that in season one, but I hope they bring it up at some point.
As for the rest of the crew, they're a good balance of wisdom and comic relief. I'm not sure Sabine has really found her footing yet, but I think Hera is one of the best "new" Star Wars characters in a while, and Chopper fills the sarcastic droid role well. The villains are interesting enough, too, with the comically named Agent Kallus doing a good-enough Prince Charming impression to feel like a threat, along with the Grand Inquisitor fleshing out how the Sith are expanding their dominance (although I'm not entirely clear on how this fits with the whole "only two" lore, which I guess has been confusing for a while).
Though, speaking of confusing lore, Rebels squarely falls into the trap created by the whole Vader/Luke father/son dynamic: the Star Wars timeline just doesn't work, does it. Luke is around 18 at the start of New Hope and even a conservative estimate of timescales means that he can't be more than 30 by Return of the Jedi (and I'd argue is likely much younger). So this grand Empire lasts less than a few decades! What's more, by the time of Rebels barely a decade or so can have passed, but the Jedi are considered an ancient and forgotten religion, the Empire has raised generations of a new army (having sunset the Clone Trooper programme with Order 66, apparently), and seemingly conquered the Galaxy pretty much immediately. They've had the time to destroy Mandalore and commit at least one genocide, but even that feels rapid given the short timespan. It just... doesn't make a huge amount of sense? For all their flaws, I think the prequels did a good job explaining why the Senate transitions to backing the Empire, and I see that the whole Clone Wars cover story was designed to put Palpatine in a position to quash rebellion before the takeover even happened, but I'd still expect a bit more resistance and a bit less immediate brainwashing. I guess our own history shows that these things can be very fast, though, so maybe that's the point. Still, it all feels a bit compressed at times.
Overall, though, the show is mindless but enjoyable fun with some occasionally excellent moments of world-building. I've enjoyed the tight connections with Clone Wars and imagine that we'll only get more and more cameos as the show progresses (though hopefully not too many). Basically, I'm having fun and happy to watch more.