I also was not particularly impressed by this trailer. Other than the addition of the baby, the plot seems to be just re-treading the same ground as the previous films. Illumination's formula has been very successful, so I suppose this was expected. And I'm obviously not the target audience for it, but all the Minion gags fell flat for me too.
The best part of the DM franchise has always been Gru's relationship with the girls, so I was a little disappointed they didn't seem to have much presence in the trailer.