Well, I would say that the only Heisei-era Rider series that deserve to be remade or rebooted are the following...
-Kamen Rider 555: I think that the plot was interesting, but, I think that it lacked a good focus on the theme and the motif of the villains. Now, the whole Orphenoch King plot twist would've been handled better if the story had a better story development. But that's about it.
-Kamen Rider Ryuki: Well, just reconnect the TV storyline with the movie, Episode Final. That's all.
-Kamen Rider Kabuto: Yeah, I think it needs more work with storyline itself.
-Kamen Rider Kiva: Remove the 1982 story arc and rewrite the main storyline of Kiva with Wataru being the rightful heir and Taiga wants to prove that he deserves to be the king of the fangires and that Wataru is the fake.
-Kamen Rider Decade: Fix the actual story of Decade, by giving Tsukasa a REAL story. Namely rewrite the origins story and follow the actual plotline from All-Riders VS Dai-Shocker, then connected to the final arc with Tsukasa being the Messiah of all Worlds and a Dark Decade being the actual Great Leader of Dai-Shocker and the true Destroyer of all Worlds. But, it must be Narutaki as a loyal subject.
-Kamen Rider OOO: Just reveal that Kougami is the main villain.
-Kamen Rider Fourze: Keep Kengo dead.