This actually makes me wonder... I love the background visuals for the entirety of the backdoor realm in stages 5 and 6, and how you go through all the past stages during Okina's fight. However, how might things like the visuals or even the story have differed if Yukari and Okina had swapped places in time? If Okina was introduced as the Phantasm Stage Boss in PCB, and Yukari was introduced only now? I can only imagine something similar to what we have now, many more gaps instead of doors.

Because of how similiar-yet-different Yukari and Okina are, how crucial Yukari is in years of fandom's antics and the gap between their game appearance that affect people's opinion of them (especially Okina), I think It's interesting to think about what if Okina and the dancers were appeared instead of Yukari during earlier Touhou games, and how the fandom would've turned out.
Would people still praise Okina like beautiful goddess or super powerful hax character just like Yukari despite having more conservative appearance and less broken power? or would the fanbase be not as crazy as it has been without sexy, cryptic but lazy broken gaphag?

One thing to be sure, is that we won't have Ran and Chen('s kinda mother-daughter thing) in that What If scenario.

Edit: in ( )