I don't know what ideas or expansiveness you're talking about?
> Then again one of my favorites hard SF authors is Greg Egan, and I've heard many times that people find his work dull (which blows my mind - Egan writes some of the most thought provoking, interesting SF by FAR).
I found the metaphysical stuff in e.g. Permutation City slow and boring - it felt like he'd had a clever idea but wasn't pushing it as hard or as fast as it could go. Had the same experience with a couple of others of his (Distress and Schild's Ladder are the ones I read). To the point where I stopped reading him for a while.
I found the Orthogonal trilogy a lot better; the physics of that is a lot more interesting than metaphysics. Though as a confounding factor I do think the characters in that were much better - still broad-strokes archetypes, but not total nonentities like in his earlier work.