At one point I decided to see what really problematic barbarians will do on marathon. I XML upped their spawning rate by about ten-twenty times and made the Great Wall cost 5000 hammers.
Result (Look who just discovered Liberalism..)
(The conquest victory with still living AI civs is due to the fact that the Monarch level AIs all got slaughtered by barbarians, so I had to worldbuilder them back with about twenty longbows for supportYes, it was a silly game)
frob I'm LMAO for real