I had a very long war once with the Zulu, (thousands of years), as I was testing to see if I could do a 3 city culture win on Emperor, (the answer was no I couldn't - LOL).
My power rating was really bad with only a 3 city empire, so the Zulu kept relentlessly attacking me. I didn't have the resources to mount an attack of my own, so the entire war was 100% defence on my part. However, after circa 3,000 years the attacks started to weaken and the Zulu suddenly asked for peace, and kept asking every 10 or so turns. They weren't at war with anyone else, but as I had a lot of espionage points against them, I checked to see what state their cities were in, and they were all very small, (size 5 or less), with lots of unhappy citizens, and with almost no production capacity at all.
I assumed their cities had shrunk in size because of my Statue of Zeus, but it took many thousands of years to kick in on Emperor. I therefore rarely build it these days, as my wars are always well planned and very short affairs, so the Statue wouldn't provide me any advantage, or disadvantage, (should an enemy have it). More important than that though, the other two wonders that come with Aesthetics give you a much higher reward than the Statue, so given a choice of which of the 3 Aesthetics wonders I would build, the Statue is now firmly last on my list.
The Statue may therefore be an unbalanced wonder, as it may work really well at the lower difficulty levels, but not so well on the higher difficulty levels.
Regards - Mr P