Is the Phantom Pain about the other Snake?

My theory is that The Phantom Pain is not only a MGS title, but without Solid. If you look at the trailer, you will see the British flag. Now if you know the backstory of Metal Gear Solid games then you know that while Solid was raised and trained under the US of A; Liquid on the other hand raised under the British flag, he was the youngest member of SAS during the Gulf War.