If you just put in a chat system, I think it would be a masterpiece. Of course, not a free-for-all chat because that would get out of control with too many people talking. But if you put in a friend chat, then the game would be really enjoyable.
Besides that, the game was great and enjoyable. Also, maybe the arena could be improved by making it a little bigger and/or make it so you can kill people in your level range, for example, levels 50-60. Or else people will keep on getting angry tying to complete a quest.
I am an ios Celtic Heroes player, level 57 Warrior, and this is my review.