So...Hesei Rider intelligence rankings? This is how I see it pre-Build since he's now the smartest.
Philip is obviously the top, but perhaps not fair necessarily due to being basically a living encyclopedia---and in a way is fairly naive.
Tsukasa and Tendou are probably tied more or less, Tsukasa a bit more intelligent I'd say while Tendou has more luck and charm on his side making him appear smarter.
Emu and Tomari are probably the most intelligent due to their professions, though Emu comes off a bit dumb due to confidence issues I think if you gave them a written test he'd be one of the highest.
Haruto, Hibiki, and Godai are what I'd like to call "unknown qualities"---since they're sort of transient individuals it's hard to say where they rank on intelligence but each of them seem fairly skilled and talented in general that even if they aren't academically gifted I consider them "smart".
Takeru and Wataru both seem like gifted individuals due to their background, with Takeru (when he shows a personality) probably being pretty keen thanks to his temple raising and Wataru a skilled musician, but due to their youth strike me as a bit inexperienced. I think both of them would probably end up being pretty damn smart though once all is said and done.
Eiji and Shotaro are both kind of sort of idiots here and there, but they both seem to downplay their actual intelligence (especially Eiji depending on the writer such as in the first Movie Wars), but specialize in street smarts.
Kenzaki, Takumi, Ryotaro, and Kouta fall near the bottom as the show never played them up as being dense necessarily, but none of them were ever really shown to be particularly bright or display any unique talents to set them apart. But part of this was for the most part Takumi, Kenzaki and Kouta were fairly bland most of the time to judge, while Ryotaro was so unlucky he felt dumber than perhaps he really was. Post-series, though, Kenzaki and Kouta probably became massively intelligent due to their fates.
I forgot how he was pre-amnesia, but Shouichi always seemed comically dumb as did Shinji so I put them around the bottom or so.
Gentarou's probably the dumbest given his age, general personality, and such---but in terms of normal intelligence. You could say he excels at interpersonal relationships, perhaps naively.
Naga is secretly the best ranger on the team.
Is it even secret? It feels like he's become the "Blue" of the series, which is funny because I remember thinking at first him and Balance would be "those two guys" always in the background.