Oh, for sure, yes. Non-Euclidean spaces had been pretty thoroughly investigated in the 1860s by Riemann and were then shown to form the basis of gravitation and cosmology by Einstein ca. 1916. But still, I think there's a hell of a lot of potential, from a 'cosmicist' POV, even in these 'vanilla' non-Euclidean spaces, simply inasmuch as they imply a universe whose basic structure and physical shape is quite literally impossible for us to imagine. That's without even going into the question of "If our universe is really a four-dimensional structure, whereas we previously thought it was three-dimensional, what might be lurking out there in the
fifth - or sixth, seventh,
nth - dimension?"
"Not in the spaces we know, but between them, They walk serene and primal, undimensioned and to us unseen"
(yes, that's from memory, sue me

)
I often wonder what HPL would have made of modern physics and cosmology, I mean extra dimensions and crazily convoluted superstrings are pretty freakin' Lovecraftian, aren't they? And it's not just in theoretical physics, either - an ex-girlfriend of mine a few years back did her PhD on a search for "extra dimensions" at Fermilab (the big particle physics lab outside Chicago). One of these days I'm going to write a story about some physicists who actually succeed in finding these dimensions, and what happens when
Something starts to seep into our little world - our "guarded threshold" - from the
Outside...
Vital reading: "Exotic spheres, or why 4-dimensional space is a crazy place" -
http://plus.maths.org/content/richard-elwes (executive summary: why Yog-Sothoth is a hypersphere

)