Failure possibly but not success. Pioli will tell you that a GM's job is to get the HC what he needs. Not all GM's ascribe to that theory, however. Many get what they want and expect a HC to make it work.
Bill has total and final football ops control here. That's been his situation here since 2000. He and Pioli (whom he first hired in Cleveland and trained as a scout and evaluator and cap manager and brought to the JETS with him when he rejoined Parcell's) had a unique relationship considering Bill was his mentor and his boss here yet he valued his input. Pioli claimed that if they didn't agree on a player they simply moved on. May have been the case with Ed Reed, since Scott was the more character-centric of the two. Bill regretted that decision. Pioli seems to be bending to Haley's wishes in KC even though he is Haley's boss in that situation. But he is also possibly regretting that.
Take away his Bill's control and you can see what kind of HC your new GM comes up with and whether or not they can even work together...based on this team's performance on the field. Because I guarantee you Bill won't remain here if he is stripped of his defacto GM duties. We have not employed a GM in over a decade, just a director in Caserio's case or in Pioli's case VP of player personnel who reports to Bill. You may want to try something different in order to test your assessment theories because the team hasn't won a playoff game in the last two seasons. Personally I'm not foolish enough to care to... And I'm relatively confident Bob Kraft isn't, either.