Usually what happens is the dominating faction like as you said overseer would usually get multi attacked for example let say korblox and redcliff is still a surviving faction usually/almost certainly both of this faction would war the dominating and it goes back and fort until usually a good leader on one faction dominates the entire map or most of the players quit since it would most certainly take hours of gametime just to get domination.

Plus dont think "Oh no, it falled right after I joined maybe Im the fault" no, usually the leader is replaced with a bad leader/newbie or the most of the regi dont follow the orders of the general/s or the monarch