What does the Clone Wars animated series add to the recent Star Wars Trillogy?

Question

I've just seen a completely epic trailer for some of the Clone Wars animated series. It looks like it fills in

how Darth Maul came back to try and take revenge on Obi-wan

I know this story from research, but it piqued my interest as I had assumed that the show was mostly filler and didn't contribute a significant amount to the Expanded Universe for Star Wars, not did I think it related much to star wars canon of any level. Is that so?

As well as this, the publication of this raises Maul's story from C-Canon to T-canon. Is there new content from this show that effects the Canonicity of other aspects of the EU?

Answer 1

Roughly, it adds these things:

1. A more fleshed-out arc for Anakin's transition from Jedi to Sith.
2. Additional attention to various niches within Star Wars canon that the films could never spend time on. The Witches of Dathomir arc is an example of this. As you mention, this show's work in this area also provides T-canon, instead of the books' C (or S)-canon.
3. A thorough view on the events of the Clone Wars. This is an epic conflict that reshaped the galactic civilization. Having more than ~6 hours to devote to it enables deeper storytelling.
4. You get to see Jedi in action on a weekly basis. Who doesn't love seeing lightsabers in action?

Answer 2

I haven't seen the volume 1 disk, but the last parts of the volume 2 disk leads directly into the opening events of Revenge of the Sith, showing the assault on Coruscant and the kidnapping of Palpatine.