The story is serviceable and it seems like it was solely created to get Wonder Woman to present time (see: Justice Society: World War II) with Batman and Superman, so that they can lead into the next movie with the complete league.
Based on this movie's ending it seems that they are heading into some kind of event akin to "Crisis on Infinite Earths" which means that movie is going to finish the Tomorrowverse continuity. This is most likely because of the DC Studios announcement via James Gunn where he said that going forward all DC movies, shows, games will be connected and will have possibly the same actors working in all platforms. If this is the case, then it makes sense to have this movie and the next to reset the animated movie continuity.
Regardless of the context provided above, this could have been better written as Warworld provided unlimited opportunities for a movie backdrop. Warworld is one of the most imaginative places in the DC Comics to draw story from, which in turn makes this movie all the more disappointing as I had high hopes for it.
