Given how it's pretty much confirmed how the next Rider will be a guy *mumbles something about 40 years*, there's really no discussion for having the next Rider be a girl.
But, seriously, a main Kamen Rider being a josei senshi would be excellent, if Toei wants to give something new and fresh each year, they should go for this.
This is a thing that I, to this day, spend days trying to come up with reasons why they haven't done it already.
And people, let nobody tell you otherwise, Larc.just.sucks.
You mentioned something in your DecadexDouble review about liking the idea of Tackle being the Kamen Rider Guardian Angel.
If Misaki Yuriko isn't a Rider, which is actually ok with me given the explanation we saw in Spirits (although what you say puts me into a lot of thought), thinking of her as the figure who watches over the Kamen Riders is PERFECT.
There are people who aren't Riders yet are as great as them:
Taki Kazuya, although you cant count him as Skullrider.
The first oyassan, Tachibana Tobei.
Even Genjiro Tani is good.
Detective Ichijou Karou
And Denpa Ningen Tackle, fits in this category as well. She does not need to be a Kamen Rider to be remembered and loved by the fans, she's that damn good, and her not being a Kamen Rider just ended making her more legendary from my perspective.
And we mustn't forget that in BLACK's world, there are no past Riders nor any connection to other Kamen Rider series (which was all fixed by Decade in a sense), so in context, there is nothing to base upon the title of "Kamen Rider" because BLACK is the only Kamen Rider in his world due to pure coincidence of using the name as a sign of his will to fight evil.
No, this is the wrong idea.
The fact that no previous Riders returned in BLACK does not mean it's a whole different world. Decade had a BLACK world, but it was a completely different one, an AR world.
Black is Black RX, and Black RX gets the previous 10 Riders back. If we went by this logic, Amazon would be in a separate world as well.
It's like when people say ''V3 World'', ''X World'', ''Skyrider world''. Such things are all the same, Riders 1 - Black RX are all in the same world.
Your point might be correct though, although not for the reasons you say. There's a possibility Minami Kotaro didn't know anything about Kamen Rider, yet still used the name out of coincidence.
Hence the reason as to why a lot of people were disappointed with RX series and doesn't really count it to be really connected to BLACK series.
That's just an opinion.