From now on, I will play a different civ each week in ranked multiplayer until I've played them all.
Update (30 Aug): I've completed the civs initially planned and have decided to add in those civs I've last played years ago, long before DE. I will also do the African civs once the expected rebalancing has happened.
Update (7 Nov): The challenge is completed! Thank you everyone for your input and encouragement!
Update (8 Jun): With the release of Mexico a while back and now Italy and Malta I've added those civs to the roster.
The first civ in this challenge for me are the British in the current week.
Who else here has never played the majority of civs in multiplayer? If you're interested to take up the challenge, post below with your own civ list and give progress updates as you go along!