I agree that we need options for keeping guys in their aircraft, but I don't think the WO is the solution for many communities.
I wholeheartedly disagree that you could replace every pilot with a warrant. Hopefully you agree that not everyone can be a Naval Aviator. It takes some level of intelligence, dedicated work ethic, hand-eye coordination, expeditious decision making ability, and the capacity to multi task while keeping SA to a multitude of things. A college degree shows that you are at least somewhat competent in the first two categories. Are there outliers? Sure. But showing that you can focus long enough to get a 4 year degree is a good indicator that you can handle the stresses and workloads of flight school, and the fleet.
The task loading put on an aviator acting as the strike lead for an Airwing strike is a lot different than on a guy whose job is to take off from point A and then go land at point B. There might be areas where the warrants would work, but there are also areas where it definitely would not.