While the second season of Dragon Ball Z was currently in syndication on TV, three Dragon Ball Z movies were released directly to home video, now looked upon in a sort of trilogy fashion.
Other than the Toriyama of it all, there's no reason Dead Zone should be non-canon in a post-Dragon Ball DAIMA world.
Toei Animation producer Takashi Washio wants to focus on works that are more globally conscious in the future, for both anime ...