!? What are you guys talking about? Goku didnt dodge that enery disc! It cut threw his neck like butter, causing his head to fall off!! Freeza then won and became the strongest entity in the WHOLE galaxie!!!
Yeah, thats a great ending... Son Goku Dodged so then Son Goku could win... and he didnt even dodge it completely it cut his cheek. Why would he get a Zenkai from Transforming. When you Transform you get stronger. Then when you revert back you dont revert back to the state you were at when you transformed. Its like his powers in base were restored not increased.