I beleive allowing a higher rate would be benifiical for public safety. The FCC has issues several exemptions during emergencies for use of Pactor 4. Why not make it permanent. 
Pactor 4 (not permitted because it exceeds 300 baud) has over twice the spectrum ef?ciency as Pactor 3 (which conforms to the 300 baud restriction) while occupying slightly less than the same bandwidth