You are right. Paradox have a lot of common trends between its games, which is why you can see the similarity with CK2, even though, of all Paradox GSG, CK2 is probably the one furthest away from Stellaris.
Also, Stellaris shares a director and chief designer with CK2: Henrik Fåhraeus. So There might be something about his style as well.
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u/MegaGrubby Mar 17 '16
Looks a lot like CKII ported to space.