A NAUI Master Diver and a PADI Master Diver are not close to the same thing and you cannot draw any conclusions about one from looking at the other.
The NAUI Master Diver class (the first difference, there is no PADI Master Diver class) includes 23 hours of academics and 8 open water dives. It requires a rescue dive, a deep dive, a navigation dive a search and recovery dive and a limited viz or night dive. The other three dives are electives.
The NAUI Dive Master class includes 20 hours of academics (but has already completed 13 in the AI class which is a prerequisite) and must complete 10 dives with specific skills not mentioned in the standards for Master Diver, but other than organizing and being in charge (including giving dive briefings), there's nothing in the requirements that are outside what I would expect one of my entry level students to be able to do.
NAUI instructors are allowed to add requirements to classes over and above what the standards specify.