With a POD late 1800s early 1900s pre-1914, that turns the British Empire into an "Imperial (con)Federation," with The "white dominions" being broken down and made into countries that are similar to how the UK is made up today. eg. England, Scotland, Wales, Ireland, each province of Canada, each state of Australia, each province of (the Union of) South Africa, each region of New Zealand (divided into 5 regions on North Island and 5 on South Island), and possibly some Pacific/Caribbean Islands, Rhodesia and/or Kenya, with places like India still under the same type of administration it was in OTL.
How would an Imperial Federation like this effect WWI (whether its started the same way as OTL or not, there's still a Great War). Would there be more than just the West/East European, North African and Middle Eastern theatres that play huge importance or would there be more? How would this Commonwealth have relations with the rest of Europe, the United States, India (in regards to Indian independence), the rest of Africa etc.