Tobar and I discussed the new kid already, but I'll throw my opinions out here so everyone else can see them because I know there's going to be a shitstorm.
My first thought was "Oh no, another Force-sensitive character, ugh, what are you doing, Dave?" But this follows along with my character plan prediction pretty well. We now have the Mentor (Kanan), we have funny droid(s) (Chopper), we have Jedi Pupil (Ezra) who also serves as sarcastic guy, all we're missing is the Female and the Alien Sidekick. Maybe someone who doesn't believe in the Force, but that could easily be the Female or the Alien Sidekick... I feel like whatever remaining characters we have will be what make the show actually work, though, since they (hopefully) won't be Force-sensitive.
I'm glad to see that Kanan has been pushed into the mentor role, because the last thing I wanted was our main protagonist being a PT remnant. So I am glad in a way that Ezra is Force sensitive, but I would have preferred to just have Ezra and no Kanan, because then we have a character that is discovering the Force on his own, someone who can find ancient manuscripts or something and eventually meet up with Luke after ROTJ and become a Jedi.
Tobar brought up an interesting plot that perhaps Kanan is the initial pilot of the ship and then dies at the end of the movie/pilot. This is brilliant, as far as I'm concerned. We have this ex-Jedi trainee (apparently) who has survived the purge and is laying low somewhere, knowing that he's destined to keep his past a secret forever, believing that he's the last of his kind, depressed, but still making a living. He's put his lightsaber away and vowed never to touch it again because of all the memories it brings back.
Then he finds Ezra somehow, and he feels another presence in the Force for the first time in ages, maybe he thinks it's his old master at first because he's so out of practise and is disappointed when it's just some street urchin. Then he thinks, wait a minute, I'm not the last Jedi, and he realizes that he has to ensure the survival of the order by training this kid in the ways of the Force (because obviously they don't know about Luke and Obi-Wan and Yoda).
Obviously there's some tumult surrounding getting the kid, who is a loner obviously, to agree and team up with Kanan, but eventually the kid gives in, and they adventure around and it's all fun and games.
Then Vader or the Emperor or the Inquisitor senses them (maybe this is The Inquisitor's jurisdiction) or they get into trouble and are seen/sensed to be Force-Sensitive and the Inquisitor sets out to destroy them. Kanan realizes that this is serious and that he has to protect the future of the Jedi and picks up the lightsaber again, and works on teaching Ezra everything he knows, eventually this culminates in the Inquisitor cornering the crew and Kanan pulling an Obi-Wan, realizing that he has to give his life in order to ensure that the Jedi survive. Ezra realizes this isn't a game anymore and that he has to grow up and stop struggling with his "destiny" and seek out Jedi teachings or some red herring to make Kanan's sacrifice matter and Ezra to be a Jedi eventually.
Now that would be awesome. It's not likely to happen like that since Dave talks about the potential for Kanan and Ezra's relationship at near the end of the video, but it would really make both characters work, in my mind.