Of course Oda is the only one to rank the characters, but the fact is, Marco have so much more history, more importance, he get hype of the Gorosei in person to be one potential Yonkou and defeat Teach, he is so much bigger than the 3 calamities together.
This is not my opinion, not my preference, this is the FACT that mangá showed to us, Marco is a legend, calamities are useless.