I'm assuming that most of you will have seen Godzilla by now. For those who haven't, I'll spoiler the rest of this post for your benefit.
If Toho allows Legendary to continue making Godzilla films, I think that the best thing they could do is follow Serizawa as he and Monarch track Godzilla's movements. Future films could be similar to the Godzilla animated series, where HEAT followed Godzilla Jr. as he hunted other Kaiju across the globe.
This would solve two big issues with this film. The first is that Serizawa is a much more interesting character than All American Hero Ford Brody. He has a motivation for following a nuclear dinosaur, and a strong moral compass. The second is that it would move the action away from the United States, allowing the films to go to exotic locales over the globe as Godzilla hunts his next big target. Such a simple setup, with a good chance for a satisfying payoff.
This would solve two big issues with this film. The first is that Serizawa is a much more interesting character than All American Hero Ford Brody. He has a motivation for following a nuclear dinosaur, and a strong moral compass. The second is that it would move the action away from the United States, allowing the films to go to exotic locales over the globe as Godzilla hunts his next big target. Such a simple setup, with a good chance for a satisfying payoff.