I think those that are trying to refute people showing displeasure are presuming that this 9 day tutorial period will somehow make each person a master level designer because of it.
I'd rather have access to all of the tools, and limit myself as I learn on the go rather than Nintendo limit me for X days. If I'm a terrible level designer day one, then I'm still likely to be a terrible level designer when I've finally unlocked all of the tools.
The only way to create decent levels is by experience, and even then, after the game has been in the wild for ages, there are going to be some really great ones, and some really terrible ones, and I doubt this 9 day limitation is going to be the deciding factor in that. It will all come down to the creativity of the user.
With all that said, after I've unlocked everything, I won't care anymore, but it will be annoying until then.