If they are going to continue using parts of the John Williams theme, then I want the full theme to play in the sequel.
That was one area where I was disappointed in the first film. They teased the Williams theme with bits and pieces but never gave us (or me) the full theme.
IMO, if you are going to keep the Williams theme, then use the whole thing. Or otherwise just don't use it and create a new new theme.
Personally, I just don't like the modern superhero scores where it's hard to place the actual theme of the character. It's there but not as easily definable as something like the classic Williams or Elfman themes.
but maybe that's just my personal preference.