Why would Wray move faster than the plan dictates?
Even if he's a gray/black hat or a sleeper, he has signed off on every termination order that has come across his desk.
Do you think they want him autistically charging after Comey et al before they have even prepared that stage?
Or is it more likely they wanted someone who could handle pressure and criticism from all sides while maintaining the status quo and proceeding with the cleansing of the organization in routine and unremarkable way?