It's understandable - somewhat - that the trailer would fail to show too much of Rocket Raccoon, War Machine and Nebula. No matter how big a fan you are of them, they aren't part of the original Avengers team and we've been primed to expect Endgame to be the culmination of their stories. To focus on Cap, Iron Man, Thor, Hawkeye and Black Widow more than anyone else, in that respect makes a lot of sense.
It particularly makes sense because of the emotional trajectory of the teaser. We're shown a reflection of the complete journeys of each of them - from Tony's first days "escaping the cave" to Cap's romance with Peggy, Thor's lost home world, Hawkeye's lost family and Black Widow's relationship with Clint. The trailer goes heavy on everything they've lost and the choices they made.
But where the hell is Bruce Banner?! He's an original Avenger, has been through a hell of a lot and yet he's almost entirely absent from the trailer. Are they consciously refusing to tell his story in the same terms? There's a chance this is a decision to protect spoilers (i.e. the expected Professor Hulk situation), but his absence is still conspicuous and unfortunate (albeit apart from that one pouty shot).
Still, these are far from fatal. And now the positives...