Galactic empires, falling or not, are hand me down conventions that don't bear scrutiny any more. They're still going great guns though and it's extremely unlikely that the presence of a galactic empire is turning off new readers. Besides, as I said before, the original trilogy is about the rise of a new empire.
As historical speculation it is done with considerable freshness and some insight. In a contemporary scene where Harry Turtledove is the king of Alternate History, it is also extremely unlikely that lack of political sophistication is turning off new readers.
The psychic powers of the Mule and the Second Foundation are absurd. They are "explained" by handwaving references to mutation and technology of unspecified sorts, which makes them SF instead of fantasy. Like galactic empires, they don't bear scrutiny. But, also like galactic empires, psychic powers are still going great guns. It is also extremely unlikely this is turning off new readers.
I still expect that the whole notion of social forces carrying more weight than the heroic individuals, the basic "hard" SF idea in the original trilogy, is a turn off to the reader who approaches every work as an aid to daydreams. Or seems to, anyhow.
On a related note, in the original version of The Day the Earth Stood Still, Jesus Christ aka Mr. Carpenter (played by Michael Rennie in a performance hailed as equal to Barrymore or Olivier,) enters the temple of democracy called the Lincoln Memorial and praises mankind. This is surely more satisfying than the new version where mankind gets treated like the moneychangers in the Temple. But I suggest that it really is easily understandable how someone might think less of sentimental self praise. Why ever pretend the thought is incomprehensible?