Actually i think you are somewhat correct. I've played out of both cities, freeport definatly being much more fun 
And yea I felt the area in general was a bit tougher. If you compare say, Qeynos has Down Below, Vermin Syne, then Freeport has Thieves Way, and Edgewater drains. Or, Antonica has Black Burrow and Stomrhold. Where commonlands has wailing caves and Fallen Gate.
Personally I feel the commonlands side of things is more difficult, generally speaking. I also feel it's more fun Heck, if you betray from Freeport to Qeynos..you have to go through some of Edgewater Drains to get to the npc you need. Very dangerous at low lvls. But if you betray Qeynos...the guy you need to see in Verim Syne, is right there at teh zone in.