Well, I was expecting something fairly soon, but I certainly wasn't expecting this! Woah!
I'm going to say my thoughts and the things I noticed in the trailer:
First of all, it looks fairly promising still. I'm happy that the animation is still in it's good ol' 2D form. It's nice to hear that just about all of the LBT veterans are back to voice the Gang of Five (excluding Littlefoot, of course). Saying that, Felix Avitia has done a pretty great job, he really does sound like Littlefoot.
The animation looks like it's progressed a little bit. It seems a bit sharper than before, and the backgrounds look a little brighter and more detailed, and overall the animation looks like it'll be an improvement over the TV series and the last couple of LBT movies. The characters seem to look more or less the same, which is good. They gave the new carnivores feathers, though. Awesome!
I'll be honest, I doubted that Chomper and Ruby would be in this film, so I'm surprised to see them. I do wonder what their role will be in this film, especially since they don't seem to be travelling with the main five in the rest of the trailer. Also, well done animators for giving Chomper two fingers again! Well spotted, DalekDino!
The baby swimmers are adorable! I'm guessing that they might be Ducky and Spike's new siblings?
I haven't actually heard of Reba, but it looks like she'll be voicing our new character for this film. I wasn't expecting a flyer of all things, but she actually looks like a pretty interesting character. I'm assuming she joins the gang to help them look for Bron, and appears to comfort Littlefoot along the way. 'Look for the Light' sounds quite nice from the snippet I've heard so far.
I wonder why Bron ended up going to the fire mountain of all things. It doesn't really seem like a very good place to go, whatever the reason. I wonder if it's anything to do with the snow, although I'm not entirely sure what the connection could be there. I also wonder what happened there that prevented him from coming back. Maybe he got trapped or something? Either way, he needs to stop going off and not coming back. It's becoming a bad habit.

The only thing I'm a little disappointed about it that there appeared to be no sign of Shorty going with the gang, and no sign of him at all. I hope he is still in the film at some point, though.
All in all, it looks pretty good! I don't understand why they changed the title from 'Journey of the Heart' to 'Journey of the Brave' though, it just seems a little weird. Well, we'll just have to wait and see what other news they give us!