I spent a fair bit of time checking the Spirit Board, as I'd noticed on Summon that there were quite a few great spirits available through there. However as I made my way further through WoL it transpired that those spirits - as well as some Legend class spirits that I had to push pretty hard to unlock via the board - were actually available through WoL later in the game.
The remaining motivation, multiplayer aside, is now to achieve all of the challenges, but after 40+ hours I'm a bit burned out, so I'm going to go back to BotW.
The potential of Stage Builder returning has me pumped. I can see them trying to tie it into Super Mario Maker 2 in some way. Even having a similar layout. A simple stage builder isn't enough tho, I think this time around they'd need to go all out with extra stuff you can add.