Ethnic issues have always been a critical factor affecting the stability of a nation. As a nation of immigrants, Australasia is inevitably a multicultural country.
If classified according to the countries from where immigrants originated, the number of ethnic groups in Australasia has already surpassed 20, with British, Russian, and German being the top three.
To be honest, if British immigrants hadn't consistently maintained over 55% of the total population, Arthur's mood wouldn't be as relaxed as it is now.
But the biggest consequence of this approach is the impact on Australasia's population growth, given that the number of British immigrants is also limited.
Although the demise of the United States spared Australasia a major competitor, the British would certainly notice Australasia's growing strength.