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@Commissar Fuklaw I can't reply directly...
My read on the intro to the first Sun Eater book feeling like Kingkiller is that may have been forced on Ruocchio by DAW editorial. He has the same publisher as Rothfuss, and unlike Rothfuss, he's actually writing books, so...
It's an issue with a lot of DAW titles in the late 2010s. They'd sunk millions into Patrick Rothfuss, and he was even by this point clearly never going to write another book, so they tried to MAKE the next Rothfuss.
Rothfuss wishes he had a fraction of Ruocchio's talent. Thankfully after those few opening bits, Ruocchio stops the imitation entirely. Not the least of which, book 7 comes out this year, and we actually WILL get to see a Sun get eaten.
As for the Dune comparisons, I think they're accidental. Ruocchio had admitted in interviews he intentionally avoided rereading Frank Herbert or Orson Scott Card and other authors who tackled similar epic space opera to avoid accidentally pulling stuff. Some of these things are just what happens when you write epic space opera (ie there are only so many ways to get around lightspeed to name an example).
Space Rome you got him dead blank, but it works because Ruocchio clearly knows his shit regarding the history and myth of Rome, because he does it damn near better than any other author I've seen.
You want a bad modern Space Rome, pick up Ann Leckie or John Scalzi.