The Professor Layton games have been popular for many years with their bright, quirky and varied characters and the intriguing puzzles that players have to solve. It is a world that thousands of people enjoy, which is why I think this would be a successful Lego set.
My idea is based on the most recent entry to the Professor Layton series, Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy which was released on both the Nintendo 3DS and Nintendo Switch, as well as an app version on mobile/smart devices. This model recreates the Layton Detective agency which resides on Chancer Lane, London. This building is the office for the daughter of Professor Layton, and main protagonist of Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy, Katrielle Layton. The model itself includes the main office space with a desk, sofa, table and chair, layed out exactly as it is in the game. The second floor includes Katrielle's bedroom, while the top floor houses a collection of golden trophies that reference some of the cases included in the game.
Also on the top floor is a collection of 'puzzle tiles' which are basically lego tiles with puzzles printed on them. As demonstrated in the pictures, each puzzle has two tiles; a 6x6 tile with the actual puzzle on it (taken straight from the game) and a 2x4 tile with the answer. Each tile has a number in the top corner, with the answer tiles having the same number as the puzzle they pair with. This, to me, is the most important feature of this build as the main draw of the Professor Layton games is the interactive fun the player gets to have solving each puzzle. If this idea was to be successful, then hopefully other clever puzzles could be worked into the set.
The proposed minifigures for this set are: Katrielle Layton, her assistant Earnest Greeves, their talking dog companion Sherl, their friends and occasional rivals Inspector Hastings and Emiliana Perfetti, and the super hero Ratman who features in one of their cases. Also included, would be minifigures of Professor Layton and Luke, the two protagonists from the previous Professor Layton games.