I'm so glad they're doing this! I loved the heck out of the first and second ones, and am happy to see they're doing more with it than just the 3ds remake! Multiplayer on the switch will be excellent! Also I think my favorite part of all this is how the comment section for the trailer is flooded with Hotel Mario jokes.
Because this thread was initially intended as a speculation thread since Luigi appeared with a new model of poltergust in the new Smash Bros. There wasn't a whole lot of time to actually speculate though since the game was officially announced not long afterwards.