i always had the idea of the next Wario land game centering on Waluigi, maybe call it Waluigi land: Wario land 6, similar to how the first wario land was the third super mario land game. the game goes down like this
Story: Wario is getting ready to celebrate Waluigi's birthday with the help of his friends, when suddenly a hooded figure show's up knocking at his door with an army and a weapon of wario's past, the black jewel from Wario World. the figure kidnaps wario and his friends and takes them to his castle, we then cut to Waluigi in his own house practicing tennis when he recieves a letter from Wario in his mail, telling him he has a surprise for him at his place. it's up to Waluigi to travel around the world and go to Wario's house to see this "surprise", all while collecting tons of treasures along the way, while the hooded figure has a surprise for him.
the game would play entirely like a Wario land game and would bring back the transformation mechanic of previous games as well as new mechanics such as a few chase sequences and vehicle segments, as well as the timer from Wario land 4 and shake it.
The Game would also include captain Syrup as a recurring character with levels of Waluigi escaping her ship blasts.
the game would have 6 worlds
World 1: Jungle land: a generic jungle world.
World 2: Dry bone Dunes: a western desert graveyard inspired world.
World 3: Factory Forest: a forest inside an industrial factory.
World 4: Orbital way: a space level where you visit alien planets.
World 5: Warui Island: an island inhabited by people with the proportions of Wario and the people of diamond city who follow the philosophy of Wario. they know greed is good. this island would house levels inspired by previous Wario games like a beach level inspired by wario land 1 and 3, or a festival celebrating Wario. as well as references to previous wario games. the main capitol is Greedville.
World 6: Diamond city: in complete ruins under the rule of the Hooded Figure.
(Spoiler alert: the hooded figure is rudy the clown.)
if my idea doesn't work then they can just make a new Wario land game with waluigi as player 2.