One thing I noticed with the Treehouse stream is the lack of minigames from Mario Party 4 onwards. There is one minigame called "Tread Carefully" which is not the name of any of the minigames in the first three Mario Party games, and if I were to guess it would likely be Sneak 'n' Snore. In general it's interesting how there is a smaller number of minigames from those other Mario Party games shown so far, with none of them coming from Mario Party 8 at all.
Also something that I'm sure a lot of people noticed is how Daisy isn't anywhere to be seen yet while Birdo is shown to be playable (in a long time), though I'm sure Daisy will be shown off at a later game.
Among returning boards, Waluigi's Island would be a very good one to return to, because it has a lot of fun events like the exploding zone and the island that changes space types every turn. It would also be nice if a "Mini Game Stadium" would be in this game, basically a simple board that is only focused on coins and the minigames that ensued based on the spaces landed.
I do agree that the Reverse Mushroom (or a Dice Block equivalent) should return, because that's one of the reasons Mario Party 3 has a relatively deeper layer of strategy of all the Mario Party games, among other reasons (branching paths with blocked entrances, action time, ability to carry 3 items that are generally more available).
Thank you for reading.