Eh, I don't think Masked Rider Den-O is better than Kamen Rider Den-O. If we were to translate every japanese title to english, then some titles would be very awkward. Like say Utawarerumono, try translating that and making it sound good. Or even Yu-Gi-Oh, an anime that most people know of. You could translate that to Game King, but it doesn't really work that way. Also, all the previous Kamen Riders have been named Kamen Rider. Just my thoughts.