OP pretty much said it all. Heroes of different ethnicities would be nice too. Okinawan Rider anyone?
It would definitely help push the whole idea of rebels fighting against greater odds of the original Rider.

I would also go back to the idea of Kamen Rider being a monster. Not like the incidental lip service of Drive or Gaim either, I mean like realass growling monsters. If not Shin then something along the lines of Gills. A monster who fights other, horrible monsters.

there are riders that do have varying origins. they probably just don't have that many okinawans because they mainly do their filming in (what I assume) is Tokyo.

and the human forcefully turned into a monster thing kinda might not be done again, considering there's a lot of children fans, many of them wanting to be able to emulate their favorite hero, or put themselves in their shoes.

and technically, Gackt (who is the Decade world Riderman) is an Okinawan.

Fun

I wanna see some foreign riders. I mean the only foreign one I can remember is psyga and I wanna see some more riders that are from different countries like let's say a Singaporean rider. Wait in Singapore one of the main languages is English so it'd be psyga all over again.

Well, Psyga is the only current foreign rider.
However, Eternal's actor was South Korean (I don't know if that counts, though).

No, Eternal's actor is Japanese. It's Mitsuru Matsuoka, who also voices Kamen Rider #4 and who sings the Opening for Drive.
The Korean actor in W was Gong Teyu who played Utopia Dopant/Jun Kazu.

The actor who played Kamen Rider Verde was half-American, btw.

tbh, they probably can't focus too much time on diversity considering they have a weekly show to make and keep up with for an entire year.
including movies,
live shows,
and other such happenings

I don't really mind the lack of racial diversity, since Japan is a very homogenous society anyways, so trying to force in more foreigners in a very Japan centric show, wouldn't be the best idea.

I do agree on having more relevant female characters. Not just pretty girls that stand around, but are involved with the plot constantly. Maybe even a Female Rider suit that isn't colored pink and/or white?

And for the less complicated remark, do you mean needlessly complicated, or overall complicated? Because those are two different things. I think the only Rider show I've watched where it needlessly complicated things was Faiz. But stuff like Gaim and Blade are a good kind of complicated.

there are rider girls that aren't pink or white.
http://vignette4.wikia.nocookie.net/...20120323092428http://vignette2.wikia.nocookie.net/...20100326005717http://vignette3.wikia.nocookie.net/...20130816231411http://vignette3.wikia.nocookie.net/...20130303055039
(technically, most of Nadeshiko's suit is silver)

http://i.imgur.com/OC4a12e.jpg
Eternal is Eternal, regardless of whether or not he's wearing a trashbag as a cape.