The producer tried to cram way too much stuff into 100 minutes of film. There was no character development, huge elements of the story were omitted or glossed over, and who the heck knows what was going on the entire time... That was a train-wreck.
I suspect that the film was going to be way over budget if they tried to create the battle-room scenes with squads of kids flying all over. I don't believe that it's possible to create realistic zero-g interactions between mobs of people using wires... The whole scenes would need to be animated, at huge cost.
I hope that, someday, this movie is re-done as a 3 part anime series, allowing more like 6 hrs to tell the whole story. Look at "Macross Zero" for an excellent example of this. An animated format would let the characters be presented at proper ages, allow for way better zero-g fighting and battle room scenes, and so much of the story could be left true to the book.