I've never watched it as I can't speak or read japanese, but something about it is really fascinating to me. It may be because its one of the last unsubbed sentai series.

I see. Well, it is worth checking out cause at the time it did some new things looking back. They were the first teenaged sentai team ever, first team to be based solely on cars, first team to have three robots, and the first team to reclaim the suffix "-ranger" since Gorenger(yes, the spelling is not identical, but it is written the same in katakana), and is the first Heisei Super Sentai team.

How do you picture Kyuranger into Power Rangers?

I'm kinda thinking they'll do a lot of homages. Maybe polish off some of the ideas that were considered for a Go-Busters adaption, like setting it on Miranoi. Do various callbacks. For example make one of the mechanical rangers an Alpha model, have the red ranger be related to Mick, say the gold ranger is a reformed member of the Machine Empire.

I expect though what we'll get is a bunch of high school kids and a space warlord who makes his monsters big through shooting a laser at them again.

So I got a friend into Sentai, and he's been wanting to brainstorm a series, and I told him it's a good idea to layer themes. I also had to point out you can reuse a theme like Dinosaurs and Ninjas have been. He then suggested subterrainen villains, and I had to point out that's been done. But this got me wondering a few things.
Other than the Tube Empire from Dynaman have any other Sentai foes been from underground?
Is there any type of origins that haven't been used for Sentai/PR villains by now?

Either RPM II or a Star Trek homage show

I can't imagine how would be the sentais of the 2020's.

Spandex costumes, has a red ranger and a blue ranger, newbies in Japanese showbiz hired to appeal and show their potential as performers, and most of us will probably still see it hate it or love it. And the occasional innovation.

What about the themes ?

For fucks sake man the 2018 series hasn't even aired. Sit down before I take your sugar away

Funny, Ohranger was amilitary sentai but the mechas doesn't looks like military.