[FairyKing]

It's definitely a difference between them, yeah. I think it connects to how in Sentai the villains are usually some external threat from space/another dimension/the distant past/wherever and are evil because they just are, while Rider villains tend to come from within humanity in some way (even the ones that aren't human in origin usually masquerade as humans or are led by a human) and often have an element of tragedy to them.

Riders regret fighting because their enemies aren't inherently evil, they're people just like the Riders themselves, who could have been good if only things had turned out differently but now need to be destroyed to stop them hurting anyone else. Personally, I like that approach a lot more than simple good-versus-evil.

I've also noticed Kamen Rider tends to be more skeptical of institutions and authority. It seems like every single powerful organization in the franchise, even ones that appear to be supporting the heroes, eventually get their flaws exposed, whether it's that the organization itself is evil or just that there are corrupt elements within it. Whereas with Sentai, it seems fairly common to have organizations supporting the heroes that are just presented as good without that ever being called into question.