I'm guessing this is based off if Kira won all his battles. Though in the end, he walks off to bring his justice to the shimgami world. That is a win for Kira.
I get how this is good for Kira fans, but I stopped liking Kira the moment he killed L, to put it simply I'm happy with the ending the anime gave us with him dying.
If anything I would rather have a ending where L somehow survived (yea I'm a L fan) or at least somehow became a shinigami himself, guess this is why I enjoyed the movies dedicated to him so much, it did more justice to his character in my opinion.