What would it take?

I know this is going to sound crazy...but what would it take to switch to a 3-4 defense.  I know we don't have the personnel to run a 3-4 defense, however I can counter by saying that the results suggest that our personnel don't fit the 4-3 either.  I'm not sure what it would take, but what I am sure of is that what we are currently running simply doesn't work and I think we need to try something new...why not change the entire thing to instead of another version of the 4-3.