Although I do think it would be nice to play with the Japanese (for some reason, I have the most lag when playing local splatfests), I am kinda afraid they might reinforce the popularity curse further.
Funnily enough, Japanese Splatfests are a little more even in that regard: 7 of the victorious teams may have been less popular, but the other 6 winning teams also had the popularity advantage, the most recent being the Dragon Quest one. And for what it's worth, five of those 7 victories occurred after the 6x multiplier was added. A similar situation exists in European Splatfests, where the ratio is 8 unpopular wins and 5 popular, and where those victories are a little more spread out so far as I can tell.
The NA region is literally the only place where the "curse" can be considered a probable thing. And with 2/3 regions having a better track record in this area, I wouldn't be so quick to assume that this curse is automatically going to carry over.
I bet there'll be "conspiracy theories" or confirmation bias with whoever wins. Callie wins and it's the popularity curse. Marie wins and it's the Squid Sister win streak.
I dunno, I think she kinda deserved a break from having her teams' ***** getting kicked month after month. And after this Splatfest, I wouldn't mind if she kept that streak going for a while longer.
Also, minor nitpick, but worldwide Callie was the one with the Squid Sister Streak up until February, in addition to the "curse" here in the Americas.