Part of me wonders if all of the "fans" hating on this movie are expecting a serious Dragon Ball Z action film, rather than a film based on the original Dragon Ball story which was a stupid, goofy comic. Literature it was not, and this movie captures that pretty well. If anything, the hate reeks of OMG HOLLYWOOD RUINING PRECIOUS JAPANESE CARTOONS, without really taking into consideration how stupid and silly the comic was in the first place.
That works for comments like the "characters aren't accurate," what are you expecting, blue hair on Bulma? Have you seen cosplayers with colored wigs? They look terrible.