In a sense the JPS+ algorithm seems to be to be turning the grid into s kind of nav mesh and if you were to explicitly do this instead you might actually get a

In a sense the JPS+ algorithm seems to be to be turning the grid into s kind of nav mesh and if you were to explicitly do this instead you might actually get a better and more general solution that's also easier to update in real time. The boundary checking improvement would be simplified by dividing the map into islands divided by gates (per his closing remarks) limiting the damage to precalculated data from changes to the map (assuming they occur in one island at a time)