This is not something Vegeta has ever done in the regular series. He shows fear of this warrior and freezes up at the sight of him basically conceding they had no chance against him.
For some reason Vegeta is completely out of character here. Still, while it is good it has its faults as well. A bit more buildup to follow, when I first saw this one I was very worried that there would not be enough time for a decent fight, but thankfully the longer running time meant there could be one giant fight between the Z fighters and Brolly who was the legendary one. The thought of challenging this warrior leads Vegeta onto the ship to the new planet with quite a few Z warriors in tow. Well he is not really interested until told of the legendary Super Saiyan warrior creating havoc. He is a Saiyan and he wishes that his prince return to the new Vegeta planet. This one has a strange mysterious alien getting Vegeta to his planet.
Why does the simple increase of length help the movie? Well for one thing they had time to set up the movie while still having a decent fight at the end that is just not another 2 minute fight where someone powers up and decimates their opponent like in the first film with Cooler. That may not seem like a long movie, but compared to other Z movies it is a nice bit of time indeed. This Dragonball Z movie actually has a very decent runtime of an hour and nine minutes.