[KyoryuGreen]

Kuuga: Make Ichijou a secondary Rider, something like G3's predecessor. Also make the ending a bit better and better final fight scene.
Faiz: Make Kaido Delta, and make Kiba Orga in the series rather than just the movie. Also make Kusaka be able to kill the Dragon Orphnoch and take out part of Smart Brain. Also have Takumi and Kiba be on the same side more rather than against each other.
Blade: Have Mutsuki not go dark and confusing like he did for the middle of the series. Also have Mutsuki and Tachibana have King and Jack forms too. More of the 4 Riders working together.
Kabuto: Drake be in the series more, he was wonderful sucks he wasn't in it more. Kageyama actually live up to his potential and become a hero and turn Yaguruma to the good side too instead of how they went out. Tendou be a bit more human. Also Hyper Gatack showing in the show too.
Kiva: More use of Ixa's whistles to get the weapons from Kiva, more use of the of the other forms of Kiva. More of Otoya in the present. Less Wataru being so depressed that he tried to erase himself. More use of Jirou and the others in the present. Probably seeing a second Ixa in the present because 20 years could have given them time to make a second one.
Decade: Not end in a movie and work on showing more of the Showa Riders. More use of Yusuke as Kuuga and Daiki working with them more. Also Kiva-La being more than a Movie-Exclusive Rider.
OOO: Just have more Date and the Double Births be around more often. Also I heard a rumor about Uva getting his own kind of belt and becoming Another OOO like Another Agito so I would throw that in this series too.
Fourze: I would have added more Riders than just Fourze and Meteor. Probably make Nadeshiko more than a movie Rider too.
Gaim: Sped up the storyline of the first 6 episodes so it got good faster.