You and I experienced exact opposite perceptions of the OST. Touhou 16's OST was exceedingly disappointing for me personally, with the only tolerable song being the menu theme, so I expected similar results with 17, which, to a degree, happened, with a few songs appealing to me. The one that was most unique and appealed to my sensibilities being the final boss theme, due to the dramatic opening and the extremely catchy melody that appears in the second half. It fully rivals Junko's theme in terms of fulfillment I've had with it.
Interesting, Sukuna and Okina's both are my two least favorite Windows Era boss themes due to lack of intensity.