On the other hand, @The_Supremes makes a good point: when a storyteller abandons a plot, or worse, runs something that is completely contradictory to the history and timeline of the game, it's not that storyteller that's held responsible for picking it up, making it make sense, and rectifying it--it's staff.
And it shouldn't be a given that staff need to put up with ill thought-out plots just because one time this one dude had the idea to run a random thing.
That's why I advocate a tiered plot scale. On Eldritch, for example, if you wanted to run spirits, you just needed to keep it at a certain Rank. Beyond that, you needed to consult with us. This also helps you run one-offs and turn them into longer plots: this one low-level antagonist did X, but they did it because this much more powerful antagonist (whom you've now had time to consult with staff about) wanted it done, and the longer plot can take hold. Or you can just leave it at the low-level antagonist having done X sucessfully or not, if you don't feel like consulting.
It doesn't have to be an either-or proposition and I feel like insisting "let everyone do all the thinnnnnnnnnnngs!" is the best way to get the worst result. Not to mention that, in my opinion, any storyteller worth their salt isn't going to run an epic, game-breaking plot in a single night--so anyone wanting to do a one-off fun outing for a night will more than likely be able to easily use whatever is freely available without requiring staff consultation. If they can't, chances are they're not very dedicated storytellers and will flake anyway.
My view may be cynical, but it's honestly the product of my experiences in this community. BITN and Eldritch have had some of the laxest PRP policies I've seen short of games where there are none because everyone can do whatever, honestly.