I believe one of the biggest problems with the Supernovas was the number of crews in the group.
Eleven Supernovas?
Nine crews?
It should have been a single crew from each Blue Sea to challenge Luffy’s crew.
North Blue Crew = Law, Drake, Hawkins.
South Blue Crew = Kidd, Killer, Bonney.
East Blue Crew = The Straw Hats.
West Blue Crew = Bege, who later acquires Apoo and Urouge as enforcers.
Four crews would have been far more manageable and would give Luffy’s crew a far greater challenge.