I personally would have a ton of patience, because I understand that it's not going to get fixed over night. The promise with DA was that the team was still ready to be a playoff team, that was clearly not the case and I don't trust DA to right the ship.
Yes you may hire someone and in three years and it not work and have to start over, that's just how the NFL works. Sometimes you get lucky and that young upcoming OC(Sean Payton) turns out to be a great coach. Your living in fantasy land if you think the answer is just bring in an experienced guy.