I would say don't expected to be blown away. The first episode really doesn't have anything significant in it. It has some foreshadowing of what will happen in the series, and it sets up the overall storyline (which you already know if you've seen the trailer), so I'd focus on those points. I'm uncertain how much the original adults will be a part of the show, but I wasn't that excited by what they offered, particularly Bob Saget and Dave Coulier, in the first episode.
There didn't seem to be a lot of originality in the first episode, but I think they were aiming for nostalgia in episode 1. I think it will take a more original turn the rest of the season.
I think Candace Cameron-Bure is going to be good, and I think Jodie Sweetin has potential. Andrea Barber was awesome. She had the same attitude of Kimmy, but in a more matured sense. As for the new kids, it's up in the air. Their personalities haven't developed yet, but hopefully they will take shape.
So I would say, don't go in expecting the original adults to be the main focus. They are in the first episode, but I don't think they'll be in every episode. Temper your expectations, and be open minded to what DJ has to offer, as I think she's going to be the best character.
I still have to watch several more episodes before I can judge fully, but that's what I've taken away so far.