Why are the new series named after one Rider?
 

In the old days, it made sense, with most of the shows from the '70s and '80s only containing one Kamen Rider, two at the most. But since the revival of the franchise, Kamen Riders have been popping up everywhere during the seasons.

Now, Ryuki I got, since the majority of the Riders were evil, meaning the show was focused on the good guy. But Blade, Hibiki and Kabuto all feature more than one hero, so why is the title skewed toward one imparticular?

If the rumors for next season are true, that would make Kamen Rider SDF the first season named after a group of Kamen Riders, rather than just one.

While they may have different riders, they all have a main character, every series does. Ryuki had Ryuki, closely followed by Knight, Ouja, Raia and Taiga, Blade has Blade followed by Garren and Hibiki of course has Hibiki. They pick one character to center the story around to have more balance, so naturally they get the series named after them.