[Sunred]

For starters here is my pick.

Himitsu Sentai Gorenger
Tatsuya Kishida from Ryusoulger as Tsuyoshi Kaijo/Akarenger. While I may not be a complete Ryusoulger fan I loved Kishida as Bamba and I think that stoic vibe he had going would be a good fit for Akarenger.

Gekisou Sentai Carranger
Ryutaro Okada from Kamen Rider Zero-One as Minoru Uesugi/Green Racer. Knowing the man can speak some mad Kansai dialect I would love to see him go full Kansai as Minoru. And just thinking of him as Minoru in that one episode where he hauls himself all the way to Hokkaido, the most northern area of Japan, to get back the Giga Formula? That would be amazing.