As a huge Boba Fett/Mandalorian fan, I am not much pleased with what Lucas did to Fett in AOTC, and I hate what Karen Traviss did to the Mandalorians in her sad excuse for Mary-Sue Ridden literature; that said, I'm finding Boba a much more compelling and interesting character thanks to The Clone Wars (though he is something of a talkative brat who is still very much wet-behind-the-ears to a duncey degree, but I'm hoping they're setting up some character development with that), bitter as I am about his treatment in AOTC, the show makes him likable and interesting.
And The Clone Wars has given me a very interesting treatment of the Mandalorians to entertain (and it remains to be seen if it will enter into my personal canon [that is largely dependent on if the Death Watch end up taking Mandalore back to basics, though I would also like to see a return to the True Mandalorians of Jaster Mereel's train of thought]); the whole pacifist thing can be easily explained after the whole Massacre of Galidraan from Open Seasons, and it'll be exciting to see where they go with it.
The same holds true with Anakin, who I think we all believe is one of the most mishandled characters in the prequels. The Clone Wars you actually see him as a hero, doing heroic things and being a good guy who everyone likes and trusts; you're always rooting for him to save the day. It's really hard to imagine this Anakin falling to the dark side, until he loses control and you're reminded of just who this guy becomes and what the whole series is leading up to, really (and it's interesting to note that Anakin and Angry Anakin really do seem like two different characters, so you can understand where Obi-Wan is coming from when he muses that Vader and not Anakin was seduced by the dark side).
The show also makes the clones into characters, as well. Instead of a bunch of nameless, mindless drones, we get to see that they all have their own personalities and thoughts. Half the time, they're the best characters of the show, and I always love when they do spotlight episodes on them because they're really the human element of the show in a universe full of The Force, they're just your average joe soldiers with no special powers, that, plus their more human personalities make them really easy to relate to. And when they die, you feel it.
And yes, the show also makes Jar-Jar stomachable. He's still an idiot, but he's not an idiot just to be one, and as the show progresses, he becomes more competent... or at least puts his idiocy to good use. I can't believe I'm saying that.
And yes, there's flashy action and saber battles and lasers flying all over, but there are also poignant moments as well: like when Yoda inspires his small band of wounded clones; or when we see the clones of Domino squad go from trainees to real soldiers and the friends they see die along the way; or when Boba has to decide whether or not to kill his hostages in cold blood; or when the slave girl or Death Watch sympathizer commit suicide rather than be captured; or when Waxer and Boyle find the little Twi-Lek girl and have to bring her safely home; or when the Captain Keeli and Ima-Gun Di (get it?) are overrun by battledroids on Ryloth; or when Anakin goes out of control after he thinks Obi-Wan was killed; or when Anakin gets a glimpse of his future on Mortis; or when Rex finds out that he's been betrayed by his commander and his men have been attacking their brothers. There are way more than this, too, but this is what they don't show you in the trailers and previews, and it's what keeps me coming back to the series. Not the flash and the bang, but the deeper layers and meanings behind stuff, and it's just (usually) so well done and intriguing and makes sense. Filoni really knows how to please Lucas and (many of) the fans.
Personally, I feel like The Clone Wars is what the prequels should have been.