While all games these days have the option to spend money to help give you an edge they for the most part keep it fairly balanced. So while spending money gives you some perks and an edge it doesnt make it so they can walk all over other players causing them to either have a really bad experience playing the game or just plain driving them away.
As it stands right now a major cause for such unstable server populations is the fact their is no restrictions placed on money spenders. Be it the ability to rush yourself 5+ levels above everybody else or purchase troops of a quality and level higher than they themselves can even make........!
To make it worse you then brought out a patch that rewarded these players for rushing above everybody else in the form of stopping players who are half their power from challenging them........ sit there and watch that money spender while they unchallenged rape and pillage all your hard work. Working hard to level up so you can explore and capture that city in the next unlockable area...... well sorry that player that has spent money and has rushed ahead has already captured that city. Still want that city fine attack it but then experience that money spender destroy all your hardwork purely on the back of money.
I have read so many suggestions, comments and complaints regarding this issue with literally nothing being answered or addressed.
There have been some amazing ideas placed in the forums from people who have been involved or around games for years and while it might not be nice to consider or take in these ideas for pride or arrogance sakes these people really like the game you have created and want it to be enjoyed by everyone...... not just the few who spend big money to feel good about themselves.
If you want to pm me I'd be quite happy to show you screen shots of just how stupid crazy things can get when you allow 0 restrictions on money impacting game balance.