I think this is an interesting topic, with Peter Hamilton at one end of the spectrum (on the fantastic side of space opera), Alaistair Reynolds in the middle (realistic space opera), and Kim Stanley Robinson near the other extreme (realistic SF). Is there really a difference, is “science fiction” composed of numerous subgenres, or is the “realism” of KSR merely a trope?
Some people dismiss Peter Hamilton’s works as mere playfulness, without the serious concerns of someone like Kim Stanley Robinson. Yet given the metaphorical dimension of SF there may be surprising resemblances.
For example, Hamilton’s Void Trilogy explores the theme of the price to pay for the big dream of people getting the life that they want, in this case the price is that the universe is being destroyed. In KSR’s AURORA this theme is approached in a more realistic way, and the idea is that we better take care of the Earth, as there is no replacement.