This movie is soooo bad...no offense but damn no krillen? U buggin, no tail it seems...no talkin animals....and wtf piccolo reveals goku is a saiyan? Umm I could have sworn it was raditz who told him....bulma = no blue hair? Where is tien? Goku has black hair....not brown...Justin chatwhatever the hell? Damn, we slaughtered street fighter and the new one coming doesn't have ryu or ken, massacred mortal kombat 2, tmnt goes cgi n now they wanna go back to live action an now dragon ball...what next a freakin pokemon movie with no pokemon? What is hollywood thinking?
Pardoning attrocious grammar, let us assuage your qualms by taking them point by point.
1. No Krillen, No Tien
A. Dragonball is known for its expansive cast which TV shows allow for but even on Dragonball the tv show this became a detriment later on. Does everyone remember how useless the other Z Fighters became on later episodes? I am not saying Krillen shouldn't be there but they made a decision that only one friend character was needed and they picked Yamcha probably because it better serve the story. Whether this is right or not, I do not know however its a perfectly logical choice that might actually benefit the movie.
2. No tail and no talking animals
I would have liked a tail and talking animals however its a tough sell for general audiences and to be honest both are not integral to Dragonball, if anything it was to DB but not DBZ. The talking animals serve to help the setting which again is more forgiving in a TV show because your given a lot more time to flesh things out given the nature of TV especially considering the amount of episodes DB and DBZ had to work with. The talking animals would of added to the budget as well as to the task of the film-maker to make them believable and I believe its a risk not worth taking when the heart of the story is about a young boy and his martial arts. As for no tail, again believability and presentation to general audiences that is arguable considering most of hte characters lost there tail by Frieza sage of DBZ.
3. Piccolo reveals Goku to be a sayain
Its cutting down on the amount of characters as well as exposition, if this is true they probably did it because it helps with story flow. This does not betray DB and is simply a story choice, much in the same way Begins decided to make Ra'Ah Gul be the one who trained Bruce Wayne.
4. Bulma No Blue Hair/Goku Black Hair
Do I really need to argue this, this is a design choice, nothing more