The thing is, they keep repeating elements that I think are annoying. The inevitable Rider battle makes me roll my eyes. (Kuuga was refreshing in that it lacked that, by virtue of lacking any other Riders.) The annoying/incompetent main character, though... It seems to me that of late the lead in the KR series are all just annoying and mostly incompetent. While I find Tendou's incredible arrogance amusing (and, I have to admit, mostly justified), it took me forever to get over Ryounosuke's bumbling and actually like him. (In fact, I didn't really start liking Den'ou until Deneb showed up. Deneb is love.) Wataru's complete and utter lack of functionality as a human being, much less a hero, I never got over and is the primary reason I've never finished Kiba. And now we have Tsuaka with his weird photography obsession (and bizarre, incompetence and urge to use a thoroughly antiquated camera) doesn't strike me as cute or endearing. It just annoys me. It seems to me like the writers have lost the talent for writing quirky but functional characters. I mean, Godai was a little random, but he never came across as anything other than a little odd. Shouichi has some explanation for his urge to play tennis with a frying pan, and is otherwise likable. And while Ryou had serious problems, he also had reasons for them.
And that whining aside, I did just nuke through three episodes in twenty-four hours, and it's left me with an urge to go back and re-watch KR series. Heck, and maybe even finish up a couple of the ones that I started and never finished. Once I got it through my head that Kuuga world is not, in fact, Kuuga world I enjoyed the story. I groaned when I saw the next KR world is to be Kiba. We shall see if they manage enough nift in the story line that I don't lose all momentum through a world that I know I'm not going to like.
Speaking of KR series, I'm trying to remember which in the last decade I've seen and which I haven't. *counts* Kuuga, Agito, and Den'ou all the way through. Kabuto, 555 halfway through. (I really should finish those. I liked them, but they tended to eat my brain, and I haven't yet hit a point where I can do without my brain for the week or so each it'll take to knock them out.) Ryuuki I skipped on [Unknown LJ tag]'s recommendation, and Hibiki bored me to tears by episode 4. That leaves Kiba, which I most likely will never finish, and Blade, which I just haven't gotten around to. (IIRC I started it, but there was something about it that annoyed me and I just didn't get into it.)