I gotta say, I love the ambiguous ending given to the Hoppers. I feel it was pulled off excellently and believe that both Yaguruma and Kageyama died. It may be hard for some to see, but this is why I believe both of them are dead.
Kageyama says, "I won't be able to go into the light with you.", Yaguruma attacks and then we get the cut away. As he is holding Kageyama and looking up at the stars, Yaguruma says "Let's go find that light meant only for us.", or something along those lines. I took that line to mean that while Kageyama won't be able to find it in life, he can find redemption(light) in death, Yaguruma saying "Let's go", to me, insinuated that he's going to be able to join him on that journey, in death.
I really think that part was pretty damn brilliant if I do say so myself. Definitely my favorite rider death, full stop. So, while they may have not had the best story development in the series, they did have an awesome death.
BTW, Iga, do you think you'll be doing a series overview for Kabuto? As in, one of those long, review style posts on what you felt the series' strengths and weaknesses were and what could have been done to change those? It'd make a pretty interesting entry for the blog.