It's crazy how uneven and random the higher difficulty levels in Civ 5 can be. I've been trying to take a run at the Emperor difficulty for a while now and in every previous attempt I've had my back against the wall with such extreme disadvantages that I eventually gave up on each of those play-throughs. I started really experimenting with map types, sizes and the civilizations I was playing as, basically doing whatever I could do to give myself an advantage.
It turns out that ultimately the things you can't account for--the land and resources you'll be provided or who you'll immediately be competing against for said land and resources--are what truly matter. In every previous permutation I've gone up against extremely aggressive, expansionist civilizations and had little in the way of land or resources to combat their advantages. I'd get deadlocked in wars I would eventually lose or, worse, would simply have a stagnating civilization with no room to expand and no hope of winning. It's been incredibly frustrating. But this run at Emperor is completely different, so much so that it feels like I'm playing on the first or second difficulty level.
Right now I'm playing a small, archipelago type map world as Harold Bluetooth against Napoleon, Montezuma and Bismark. The land I was provided is resource rich, with everything you need to have for a strong Civ leading up to modern times. None of the opposing Civs have focused on cultural achievements because they're all incredibly militaristic and none of them have expanded near me. The worst was Bismark doing a drive-by denunciation moments after meeting me. It's almost absurd that it feels this easy.