This cinematic is to me the less exciting but by far the most beautiful and well done.
It looked amazing. The fight was Ok. The monk.. At first I didn't like it as much, just because he is not fighting seriously. The look on the orc and human face though is priceless. And the bit when "chen" straights the lantern (I think it was a lantern? i would swear i saw some smoke coming out of it) was funny and made me laugh all the times I saw it. Kinda like the human sheeping someone on the classic cinematic.
As for the end of the cinematic, I though it was ok. And here's why. They got into pandaria, they saw a pandaren, both of which they probably didn't know about. This expansion is all about exploration, so to end with a scenic view of pandaria is fine. (even though it ended with "chen").
But it needed more conflit of horde vs allience. I to me that should have been there in the beginning, we only saw 2 ships and 2 people. We could have seen more ships, more people, a bigger fight. And then move to those two and end with the discovery of pandaria. That of course is a huge thing.
That's what I think.
Oh and I think the orc and human were to amazed and confused at pandaria to start fighting in the end. And teamed up because they were getting their asses kicked with this new foe they knew nothing of.
Finally... Is that really Chen? I hope not. Because if he is.. how did he find pandaria? the mists only now cleared... and he was in azeroth before.. (and didn't he born on the turtle? so he never been there.. i may be wrong on this point). So to me its kinda strange.
Would make more sense if its a pandaren from pandaria that see two strange creatures fighting and battle them so they stop, as he said, to defend his land, and preserve balance.
PS: Yeah i was waiting for the Sha as well.
Sorry for long post.
EDIT: Forgot to mention, this is the least exiting of all cinematics because, the classic introduces the whole world and races, so it was awesome, and we saw cool spells and all that. TBC because of illidan in demon form saying were not prepared for him. Thats exiting. Arthas was awesome cause he raised a goddamn dragon and had an amazing army by his side (and his father talking helped a lot). Cataclism... well deathwing riped the world apart. how can that not be exciting?.
This one.. no big conflit, so not as exciting. But still an amazing cinematic that to me, did what it was supposed to. Revealed what the expansion is about.