Will it be better if Ken Watanabe becomes the main character in the sequel?

Agreed. Ford's story is basically over. Time for a new character.

Serizawa should definitely be the main character, even in the 2014 film I wanted to see more of him. And thanks to the Awakening novel, he has plenty of back story for me to already like him.

I agree with the above posters. I think Ken Watanabe's Dr. Serizawa should be the main the character for the remaining films of the (projected) trilogy.

He is Japan, the historic and spiritual home of Godzilla. Godzilla is Japanese, no matter where he goes, or what part of the world becomes his focus. This is because he was made a kaiju because of the Bomb. Serizawa handing his watch to Admiral Stenz was a seminal moment in the film: "8:15 in the morning, August 6, 1945 ."

Serizawa is the voice and the face of Hiroshima and Nagasaki. Watanabe carried in his face and body language the anguish of someone looking at the prospect of nuclear weapons being used and all that it entails.