>>29740926Ignoring the gross exaggeration here, this does seem like a niche with some utility. Baton Passing a Spirit Shackle lock is not something to be taken lightly, and Decidueye has both +2 boost moves. There's always a chance that the widely-swinging nerfbat this gen hit Baton Pass and prevented lockpassing, which would defeat the whole purpose of Decidueye learning it. Seems like a very GameFreak move to pull, honestly, but we will see.
In Smogon terms, I doubt it'll make OU but UU seems possible. Maybe a set with ShacklePass and Swords Dance with Leaf Blade could function as a wallbreaker who can pivot nicely to an ally, potentially allowing them to set up even further.
I would trade the viability of my other favorites to swap its Speed and Sp.Attack, though. Such a waste.