I find it ludicrous. Let's expand the Premiership into the US as well.
I could see the NFL only working in Canada and Mexico (granted players may not want to play/reside in Mexico City either) outside the US. Logistics would be a nightmare for clubs traveling to London and the London club to the US. Then the exchange rate and taxes for players based in England. How would that work out? And I find that London would struggle in the free agency department as most players would prefer to play/reside in the US.
And to give a franchise to a European city while deserving cities in the US miss out is ridiculous. Cities like Los Angeles, Las Vegas, Portland, San Antonio, Oklahoma City, an actual team in New York city, or Toronto if going abroad.