I think we can all agree that Professor Layton doesn't need to be in three dimensions, but Nintendo doesn't give a hoot about whether you think the game might be better if it stuck to two dimensions. As such, they've just announced plans to release a new Professor Layton title for the 3DS, which is due out next year.
No details about the new Professor Layton game have been released, except to say that the game will be out for the 3DS handheld in Japan sometime next year, where the game is currently being developed by Level-5. The game is expected to make full use of the 3D features on the Nintendo 3DS.
Like all the other entries in the series, an international release of the game is expected to follow not too long afterwards.
The announcement was made just now at the Nintendo Direct press event. You can still catch it here if you're not too late.