A neat thought I had:
Mario movie, Luigi gets kidnapped
Luigi's Mansion, Mario gets kidnapped and Luigi gains some confidence and bravery when on his own, instead of only when he's with Mario.
Mario movie 2, Peach gets kidnapped and the brothers, now much more adept and brave, must save her.
I just think one of the main characters getting kidnapped per movie would make for a nice through-line to tie the movies together, in addition to being accurate to the games.
And it could work well for a Yoshi or DK movie too. Yoshi would serve as a prequel, where the Yoshis protect and/or rescue the babies from being kidnapped. And could explain how exactly Peach ended up staying in the Mushroom Kingdom.
DK movie, either go the route of Cranky gets kidnapped and him and DK resolve their father-son issues along the way of DK saving him and the banana hoard and beating K Rool, or maybe Diddy gets kidnapped and DK goes to save him despite writing him off as an annoying fan, and DK's opinion does a 180 as he and Diddy end up best friends by the end. Again while the duo get back the banana hoard and defeat K Rool. Actually, that might be able to work all as one film, where Cranky gets kidnapped, Diddy joins DK to save him and they become besties, etc.
One last fun idea, what if Bowser got kidnapped and was the only hope of beating the new big bad, so they had to reluctantly rescue him and work together? That would end up pretty hilarious for a possible Mario 3, and tbh Fawful would work perfectly here. Though a new big bad exclusive to the films could also work. I just love it when Bowser is forced to work with the good guys, it humbles him in such hilarious ways. Oh! Another idea! Junior could get kidnapped and Bowser must plead for help in saving his son!
Well this ended up becoming a huge ramble, thanks for reading it! I'm just very very excited at the prospect of more Mario universe movies!
And damn, this made me realize there's tons of kidnapping in these games
