The dragon clan is cool, but I don't think that they are necessarily the strongest tribe. They have the weakest titan attack wise, because it can only use ranged attacks. Also, in order to advance epochs, you must build certain buildings to do so, as well as collect adequate resources. Not to mention that, in order to raise unit limit, you have to build more town centers. I'm not saying there bad, its just that you need to play as them for a long time in order to get used to them, and you must have lots of space and resources available to use there full potential.