On a statistically flawed polling group of 3 (three; i.e. my wife, friend and me) I came up with 3 (three) positive opinions.
Gave me an honest laugh. Loved the boy playing with toy tanks, thought it'd be Sirius. But then the first flashback came and cracked me better than a Faust cracks a T-60 open.
Wife said the beginning looked like it would be pompatic, but appreciated the light tone once it came.
Loved the sniper and the assault footage. Re: the tank sounds, Ost's sounds in that vid made me somewhat apprehensive - at first. But then again, aren't tanks coming in a later patch? That makes the absence of tank sounds more readily understandable.
Personally? Great job, TWI. For its intended purpose (as divined by the collective wisdom of fellow forumites, Yosh and my own self), it's a smashing hit.
Edit: I have to add this. As for people moaning that it's not serious, or complaining that RO was serious and this trailer shouldn't undermine that... Well, have you not ever laughed while playing RO? Have you not participated in jocular stabbing contests on RO_Sparta? Have the Easter eggs fallen on deaf ears? The Batman? Things? No? Nothing? Okay, maybe you didn't. But have you never laughed while playing a (computer) game?
What is there for me left to say? "Sad" suffices.