I watched Decade first and then went back and watched the other series that came before it. Every one, outside of Kuuga which just had some minor alterations, is massively different. Kiva in Decade is the same character, but alternate. Just like the setting is. After Decade it seems that they go along with what the new Riders are like without changing anything. Now, when Riders meet other Riders they are themselves from their shows and not an alternate version. Even if Decade is involved.