I thought it already was an option.
Personally, I'd agree that since there are options for the Union Flag or the individual countries of England, Scotland, Wales, and N. Ireland, and there is also an "International" option, then Hell, why not include the EU flag.
As for "no politics here so no flags of political entities", any nation-state is a political entity.
The European Union is a collection of states... And we couldn't have a flag to represent a collection of states, could we now, Stars and Stripes?
I've previously considered making my own flag on here the EU one (not realising there wasn't such an option), and previously kept it as the Union Flag merely to be in line with the idea of international play.
Changed it recently from the Union Flag to the St. George's cross, not out of blinkered English patriotism but rather simply out of solidarity for "Team England" on here, for which group I plan to play most of my team match games this year.
The EU as a political construct has its good and bad points... But then, so does any political construct, I think, and the choice of one's flag on here simply represents where one considers "home", when it comes down to it.
Without passing any judgement on Brussels, Merkelreich, etc, I simply feel at home anywhere in Europe. I manage a company that operates throughout the EU + Norway, I speak a bunch of languages, and travel a lot. I was born and bred in England of English parentage; my passport says "United Kingdom of Great Britain and Northern Ireland", and I consider the whole of Europe to be "home turf".
Yet when it comes down to it, I'm with Anatoly Sergievsky on the topic of nationalism:
"Let man's petty nations tear themselves apart
My land's only borders lie around my heart"
the union jack is too much for me, sod europe!