So IMO one of the things that sets this appart from other MMO's are all the little details that make it feel like a living breathing world. I am an unashamed sucker for these kinds of minute details and as such have some suggestions.

Class based activities! So my idea started when I was wandering around as a gladiator trying to find out how you enter the Colosseum/Coliseum and found that I couldn't. So my idea is this would it not be fun if there were little things that you could do like this? Enter a fight for Gill as a Gladiator, have an Archery contest as an archer etc? Since you can be all of the classes I just think it would be fun little detail to have added in so that the world feels more alive. Of course it could be PvE/PvP or both, which offers even more choice, just a little something each class has that involves it more in the world and brings it to life, something unique and different for each one that fits its classes theme and ethos.