I find Emperor now to be really hit-or-miss:
I've had several games that I had in the bag already by the Renaissance, mostly because the Zulu, the Huns, or some other warmonger started a continent-wide war on the opposite continent from where I started. In several of these particular games, I was able to hard-build wonders I usually only hard-built for gold (for getting beaten to them) in G&K, presumably because at least half the world was just trying to build units and maintain the military dead-lock.
On the other hand, I've had games where the continent opposite of me had 3 peaceful civs that traded with each other, established RA's with each other, and ended up spitting out at least one massive runaway that was way ahead in tech and went on to conquer the other 2.
The issue is that early-war, if it becomes a dead-lock, makes those AI's participating in the war stagnate very quickly due to not having trade-routes and/or focusing on building large numbers of units. Conversely, if I'm the one on the continent with two war-mongers, I may not have any safe trade-routes, nor will I be able to have RA's unless I meet the other continent(s) and the AIs on them have enough gold and are willing to DoF.
Thus, because of the peace/war dynamic now, I find Emperor games to be sometimes as easy as King or even Prince games, and in other cases almost a half-step above Immortal games, all because where the war happens and how it plays out can either cripple several AI for a long time, or cripple me for a long time, mostly now because of how war disrupts trade-routes and a couple of other issues.