To each his own, I suppose. For example, I consider Ramin Djawadi's Iron Man score the best in the line of Marvel Studios ones and many will disagree with me on that, but that's okay. That's why we're discussing stuff and share our opinions in the first place)
I think, that Silvestri will do a good job, given the proper amount of time (which he obviously has). I just want to hear a mix of different themes (Cap, Thor & IM) in one song. I'm sure there are no copyright problems with Doyle, Djawadi and Debney (although, I'm not a fan of his IM2 score).