Actually, six characters are better than 20-30 as it gives the series more of a focus. TCW was boring due to how many characters there were, and sadly none of them, besides the main three of Anakin, Ahsoka, and Obi-wan, get any real development as characters. More characters do not equal better stories, instead they equal more stuff to focus on, and most of the time not enough time to focus on them. Rebels should, in theory, be better as they have a constant main cast to watch, and unlike TCW, they seem to have a constant story of some sort going on. Granted, I don't know the quality of the story, or how often they focus on it personally, but they seem to do better than TCW did with most of it just being random battles, and characters that were just meh due to a lack of focus.
Also, Jedi Academy? I'm a little biased in saying this, but if Disney Canon is doing this, especially Falonzi, then... I'm kinda worried for that show.