Disclaimer
This is a review based on story and character development, emotional pull and action, animation and scene quality, and creativity. Each section, plot, characterization, emotional pull, scene quality, and creativity can get two points each adding up to ten points at most. A section can get two, one, or zero points depending on if the section does well, is acceptable but not great, or is just awful. I do not take into account the cost of said media or the length of the media, though I may mention it in recommendation. Thank you.
WARNING possible spoilers WARNING
So the plot to Wrath of the Dragon has little to do with dragons. An alien brings a music box to Earth and says there is a legendary hero in it. After using the Dragon Balls to release him, named Tapion, the Z Warriors find the legs of a legendary evil is roaming about. They learn Tapion and his brother had each half of this monster trapped in their bodies, and if the legs are around, his younger brother must be dead. They try to help Tapion keep the upper half of the monster in check, but with the halves being so close it becomes too much and the upper half is released. People fight, and eventually the monster is killed.
In battle of the gods, this god of destruction Beerus is awake early out to find a super saiyan god. He locates Goku and tests him but nothing happens and Goku is defeated in two moves. Beerus goes to Earth and mingles with Whis his assistant while sampling the foods. Vegeta knows the stakes and tries his best to please Beerus though eventually fails when Majin Buu doesn't share his pudding. A fight breaks out, and Goku manages to calm Beerus down long enough to ask the eternal dragon on how to summon a super saiyan god. Soon Goku is turned into this god and fights Beerus. Goku looses, but Beerus spares "most" of Earth half way due to the food.
So the plot to Wrath of the Dragon is great. The plot to Battle of Gods is... lacking. Acceptable but lacking.
In Wrath of the dragon you have Tapion and young Trunks. That is about it. There are several other characters in the movie, but those are the only two worth noting when it comes to development. Is it good development? Of course hence worth noting. Everyone else? They are there to expand the plot more. the villain isn't even worth too much character wise. That being said, Tapion the original character in the movie is awesome, and his respect for Trunks is pretty cool as well. Still, Gohan, Goku, Videl, Bulma, Vegeta, Goten, and the villain are just there for some fight scenes and to talk about Trunks and Tapion.
Battle of the Gods shows us Beerus and Whis, both humorous and interesting characters, and it develops Goku, Vegeta, and Videl further. Why Videl? She is pregnant. Goku doesn't like power he can't get to through hard work, and Vegeta as he is willing to act like an idiot and swallow his pride to save Earth and will beat up a god of his wife is hit. Also Trunks gains a 41 year old girlfriend in the body of a 10 year old. We do see plenty of Gohan's character and Goten's as well. Far more characterization here then most other movies, though it could be this movie is kind of part of the series, or that it is longer then all these other movies.
Wrath of the Dragon is sad. You see Tapion's brother get killed, and you hear of the devastation the villain causes. Tapion also asks Trunks to kill him to defeat the beast (even though Trunks never does). That being said Trunks' friendship with Tapion is heart warming. Tugs right at the feels. Also Trunks gets Tapion's sword as a gift which is a nod to Future Trunks and his sword as well as a nice moment. Also things get dramatic as the big bad defeats most of the Z Warriors.
Battle of the Gods is more funny then anything. Beerus' and Whis' obsession with food is hilarious, and Vegeta trying to entertain and keep Beerus calm is impressive as well. The action is really good in this movie, and when Goku loses his fight with Beerus, the heart may sink a bit as Beerus destroys.. a small portion of Earth.
Both movies have good moments, one is the struggle, and one is more humorous, and both movies have decent action with Battle of the Gods having far better action then Wrath of the Dragon.
Both movies are animated pretty well. Wrath of the Dragon is a bit older and shows, but it has a good quality to it, while Battle of the Gods has some 3-D effects and some nice drawn characters. None of the fights are confusing and if I had one complaint it would be Wrath of the Dragon is very dark in setting and in lighting a lot of the times. Not bad enough to warrant a mark down, but still something to look out for.
Wrath of the Dragon suffers here. The best character in this movie is Tapion. His design and the monsters design is awesome, and the movie focuses on him and it lacks the feel of a Dragon Ball Z movie. So much creativity that it literally drowns out most of the Dragon Ball Z elements including the characters and plot, outside of a few fight scenes and Trunks' development. It isn't bad, but it could have focused more on the Dragon Ball Z aspect too. Battle of the Gods however was really creative however, had great character designs, added to the lore of Dragon Ball Z well, and had a great excuse to have everyone in the movie.
If you like heavy plot elements and darker emotional pull situations but still like Dragon Ball Z style fights, Wrath pf the Dragon is short but great for all of that. If you like Dragon Ball Z lore, humor, and even better Dragon Ball Z style fights, and don't mind lacking plot elements then Battle of the Gods is more for you. Also Battle of the Gods is longer which does more to justify buying the movie alone outside of a combo pack.
Both movies are pretty good if you are a Dragon Ball Z fan and Battle of the Gods helps out newer fans as well. Battle of the Gods isn't the worst place to start if you aren't into Dragon Ball Z as of yet but are curious, though Dragon Ball is a better place. If you are looking for the overall better movie, Battle of the Gods is going to rate higher however there is more tension and actual sad and well written death in Wrath of the Dragon as well as a better plot.