This suggestion has been offered many times. You are in effect punishing the winners by cancelling all their hard work to win a world, sometimes through a long and expensive war.
Yes, many worlds are controlled by a few players. The older numbered and language specific worlds in particular are in reality dead. No new players are joining. It is never worth joining a world after even a few days as the best players have invested heavily in time, energy and money to become the best players.
I have no affiliation with EA/Envision, I enjoy my time as a moderator and don't play other games online except for a few games of Microsoft Solitaire for free. Why do I enjoy being a moderator? I like to feel I am helping out others as I do elsewhere in real life. I'm retired so have plenty of time and seem to have the skills required (whatever they are) to help. You may see it as a waste of my time, I certainly don't and I believe those that I've helped and that others have helped would see moderators as necessary part of the forums. I've even seen suggestions for in-game moderators to help reduce conflicts around the use of multi-accounts and other perceived exploits.
How long it takes to go viral on Facebook isn't my concern!