Okay, I’ve done a careful review of all of the ports on the latest draft of the map.  The list below shows all of the ports that each port 3-links to, and (in brackets), the ports that each port could 3-link to if all more-direct routes were blockaded.
The only real useless one is the port that straddles sz 10/17 off Great Britain, as SZ 10 does not 3-link or (3-link) to any other port at all.  Move it down to just sz17. (into London, why not?)
Washington S. and Japan are both pretty weak, with only one 3-link and one (3-link) each.  Other than that, everything else looks strongly interconnected.  Here’s the list:
Hawaii – Carolines, New Guinea
Carolines – Japan, Hong Kong, Hawaii, Java, Shangtung (Philippines)
New Guinea – Hawaii, New South Wales, Philippines,  Java (Western Australia)
Japan -  Carolines (Philippines)
Hong Kong – Carolines,  Java
Java – New Guinea, Hong Kong,  Madras W. (Philippines, Malay, Madras E.)
Shangtung – Carolines,  Malay
New South Wales – New Guinea, Western Australia
Western Australia –New South Wales, Malay, Philippines, Madras W., Madras E.
(New Guinea)
Philippines -  New Guinea, Western Australia, (Carolines, Japan, Java, Malay)
Madras W. – Java, Western Australia, South Africa,  Lower Egypt N., Malay
Malay – Shangtung, Madras W., Western Australia (Java, Philippines)
Madras E. – Western Australia, Abyssinia & Lower Egypt S. (Java)
South Africa -  Madras W.,  Abyssinia & Lower Egypt S.,  Brazil
Lower Egypt N. – Madras W., Gibraltar (Tunisia, Southern Italy)
Abyssinia & Lower Egypt S. – Madras E., South Africa,  Crimea, Tunisia, Southern Italy
Brazil – South Africa,  Gibraltar, Washington N. (Washington S.)
Gibraltar – Brazil, Lower Egypt N., Western France, Great Britain W. (Southern Italy)
Crimea – Abyssinia & Lower Egypt S., Tunisia
Tunisia – Abyssinia & Lower Egypt S., Crimea (Lower Egypt N.)
Southern Italy – Abyssinia & Lower Egypt S., Morocco.  (Lower Egypt N., Gibraltar)
Western France – Gibraltar,  Morocco,
Great Britain W. – Gibraltar, Morocco, Washington N.,  Germany,  Great Britain SE.
Morocco – Southern Italy, Western France, Great Britain W.,  Washington N., Washington S.
Washington N. – Great Britain W., Morocco,  Brazil,
Germany – Great Britain W.,  Archangel,
Great Britain SE. -  Great Britain W., Archangel
Washington S. – Morocco, (Brazil)
Archangel – Germany, Great Britain SE.
Great Britain NE. -  nothing
Hope this is useful!
~Josh