I did a Danish domination run on Emperor, and this looked like a piece of cake, after my struggle with Babylon and Inca, even in King. I think the lower the difficulty, the more aggressive AI becomes, and failing to provide a meaningful army is punished harder. Even the immortal Austria of the contrast game was easier.
A suspect of mine is that the highest difficulties become easier when you can finish them before AI complete atomic age.
Also, I find combat still too long and the domination victory happening too early. I won that Danish game with frigates. I'd like to see fewer units, faster combat and longer assymilation times.
Another irk is that war weariness is not affecting at all when you don't lose units. This allowed me to keep fighting and take all enemy cities without asking for truces. This is plainly wrong. At least capturing cities should increase war weariness, since those citizens are now part of your empire and they are tired of war.