Still, Kamen Rider is blatantly a kids show, right down to the gimmicks. Those gimmicks are designed for children, and if they're going to bring Kamen Rider overseas Bandai is gonna wanna sell merchandise to the intended target audience.
So that means either:
A.) A heavily edited Kamen Rider dub appropriate for children to watch.
B.) An American adaptation.
Both would probably be at an earlier time slot when children would generally watch TV.
Also anime, even kids anime, is a little more generally respected among all audiences than Tokusatsu is. Hell, the only thing most Americans know about toku is Power Rangers, and they'll instantly label it as a kids show and probably disregard it. So there is the ratings issue.