I didn’t single out
Othogonal for being (necessarily)
lesser, I singled it out for being mainfestly
different from most of his other stuff, in the sense that it occurs in a Universe with physical laws evidently different from that of our own (though his most recent book
Dichronauts, which I have not yet read, also follows in this trend of “what-if” counterfactual speculation).
To be honest I also found the concluding book of Orthogonal to be rather disappointing, but that’s personal preference.
I would have most certainly not drawn attention to the different nature of Orthogonal if I hadn’t had the feeling that the original poster is seeking for “hard sci-fi” that presents avenues for what our futures in this universe may be, as opposed to what other universes may be like.