How to get the achievement "Great Destroyer" if the AI does not build Great Wonders?
This is the only achievement I didn't get for Imperator thanks to its bugged(?) status. It's theoretically possible, since the AI does in fact build great wonders. I even saw a random tribe in Gaul with one near the end of a game once. But it's quite rare and I definitely haven't seen them build 10 in one game. Supposedly the best way to do it right now is to completely envelop the seleukids and maurya, making sure they don't border each other, and then just wait for them to build 10 between them. Since they can't really do anything else if enveloped by you and they both make a bunch of money they should build enough.
The problem with this is that you have to do it as one of the celtic tribes, meaning you almost have to do a world conquest as Audenia or whoever, in the vain hope that the AI decides to build enough wonders. The "easiest" path would probably be to exploit migratory tribe mechanics and hoof it over to the Anatolia thunderdome where you can rapidly build a powerbase and play as a very bad version of Pontus that has to civilize so it doesn't get stomped, but for some unknown reason you can't get the achievement as a Pannonian culture tag, meaning Boihaemia and its decent number of starting pops (and potential Galatia formation) are out.
Obviously if this achievement allowed ancient wonders it would be absolute cake, but c'est la vie.