A more faithful adaptation of Dragonball is necessary to make the transition from DB to DBZ. Is Goku a Saiyan? Why did they take out characters like Puar, Oolong, even Korin (who is a major player in the actual Piccolo Daimao saga)? They could have been worked in just fine if the writer(s) were at all talented, and were also fans of the series. And what's with the 'Fast and the Furious' meets Bullet Proof Monk feel? It's just a trailer, but I sure as hell hope that the movie does good enough so that someday, in the hands of the right people (i.e. true DB/DBZ fans) we may see Frieza on the big screen. Hands down the pinnacle of DBZ, just as the Piccolo saga was to DB.
For kicks, I have began writing my own DBZ screenpaly (as many probably have). I lived and breathed DB/DBZ (both english and original Japanese) for years and I guarantee I could write an awesome movie. If only I knew Akira Toriyama...