I must dissapoint you, but your points are not so ggod as you think... This is point of view from somebody who came from different game then IO and expect that all will be same here. And you cant rule the game if you play only 2 weeks and log in 5 times per day. This is war game.
First, i a here long time and i would always choose Imperians, no matter Nomads dont need houses, have cataprachts... pure economy strength of Imperian is designed to rule at the end of era, but whn you know how to play, no nomads can even catch you in the beggining. But all depends on gameplay.
And you say all stronger guys attack you... please name 1 game where stronger dont attack weaker? When you pass certain points, even 2x player isnt so much stronger in army or econmy then you, because higher fortresses, researches, buildings cost a lot for only 1 lvl. So maybe at 1 milion points you have 12 provinces, player with 2 mil have 13-14.
If you know how, he is no treat to you. Dont keep a lot of resources in provinces, spend them before you go offline, keep army save by sending it to some goldmine or player which cant defeat it. Farm weaker then you or those that are not online. Game is more balanced then you think... It take some time and expirience to get to the top.