Hongo is the one I see most working in the real world, which comes with its own set of problems that I'm glad they never have to worry about on TV. Considering he's a cyborg who also happens to be a guy who supposedly has an IQ of 600 (!), I think he's fairly grounded in reality, and is someone I would look up to.
Tendou is a kind of character who works on TV, but how many people would take him seriously in the real world? I think he'd likely get arrested if he tried to pull half the stuff he does on the show.
If Shinji were really tasked with defending the world (or Japan)...God help us. Especially considering
[HIDE]he kinda died at one point.[/HIDE]
Kagami's pretty good, but so far has just proven to be the ultimate supporting player- to me if he were to exist, everyone from his world would also have to exist. Unless we see him go a couple episodes as the lone hero of the show, so far he's just sort of been "another guy to get in the fights", and it feels like there needs to be a Tendou to be a Kagami.
Yaguruma is the most realistically feasible, since he was part of an organization and did things by the book, and had a good head on his shoulders at first. He also went totally batshit crazy though, but maybe that wouldn't happen in the real world where he wasn't being written poorly.
Minami would be my second choice out of this list, but honestly, I wouldn't want to live in his world, because as I've said before, being Kamen Rider Black sucks. That said, he'd get every ounce of my respect, but I wouldn't want to be around for pretty much everything after episode #35.
Lastly, I pick Hongo because his whole character just inspires me so much. The others are really just guys I root for for a year, and then that's about it.
But I think if there really as Kamen Rider-esque stuff going on, it actually would be like a darker version of Kamen Rider Hibiki- two secretive forces battling it out, outside of the public eye.