What We Owe Kotaro Minami in the Heisei Era
Well here's my favorite Kamen Rider, Kotaro Minami who played both the Black and Black RX series which would total up to 92 episodes (correct me if I'm wrong on this!). So while the Showa era riders were more or less the typical Toku (and please DO NOT comment asking for me to review them here, you can get a lot more reviews on Kamen Rider from Igadevil's blog!), but here's what I thought should be a tribute...
Darker storylines and cartoony storylines. Black was a darker story compared to its predecessor and Black RX was lighter and softer (which was what some fans didn't like but I was okay with it). So maybe Black RX is NOT that cartoony but I guess it influenced Kamen Rider Kiva's cartoony nature while Black influeced Kuuga and Agito. That's just how I see it.
The introduction of more cruel villains like Bilgenia. Bilgenia was one huge SOB that he really was more cruel than Shadow Moon but he was written off pretty soon thanks to the fact that Shadow Moon had to be revived to finish the series as scheduled. Fortunately we saw more of his kind in Ryuki as really evil riders.
The introduction of the evil Kamen Rider concept which persisted for a long time. However Shadow Moon was just brainwashed and crazy, the later riders were really evil at their own free will. A really interesting replacement to those false riders with yellow scarves to add real conflict. In the Heisei era, the more evil Ouja was created who was more or less another Bilgenia.
More active friends. In Black RX, you really see his friends participating one way or another in helping him thwart Crisis Empire's schemes.
Multiple Rider Forms. Black RX introduced multiple rider forms while Black (my favorite) was the last to be the rider with only one form.
Any more? Please add.