Popping back in briefly...
There's been some discussion of the pay-to-win aspect. That's actually pretty well balanced, I think. You can spend diamonds to get an advantage, but unless your goal is to completely dominate the server, you can do just fine for free. Some people game the system by having additional diamond farm cities, but even if you don't want to take the time for that, the diamonds you get from GE, GbG, etc., are generally sufficient. I think this is something they've balanced pretty well.
The thing that I hate is the mindless boring chores. That's the big turn-off.
I like spending my time solving puzzles, tackling interesting challenges, etc. Back when I had a 2-digit attack boost and fought a limited number of battles, manual battles were fun. Every battle was a tactical challenge for me to solve. I hung out in EMA for a while, and I loved my mounted archers - as terrible as they are for autobattling, their mobility is outstanding for manual fighting. Those manual battles were a lot of fun. Trying to work out a way to arrange my city to fit in as many buildings as possible and deciding which buildings to keep and which to scrap is an interesting challenge.
But when you get large 3- and 4-digit attack bonuses and start almost exclusive autobattling in GE and GbG, fighting hundreds or even thousands of battles per GbG round, it becomes a mindless boring chore. Aiding and visiting taverns is a slow, mindless, boring chore.
The balance of free players vs pay-to-win players is something they've done really well. The proliferation of mindless boring chores is something they've done very poorly.