People seem to be making the assumption that the only way to hold power in Faerún is by personal might, be it at arms, magic or otherwise. This is blatantly false. You can be a mover and shaker in the Realms from the start, if you want and your DM wants that sort of game. I'd suggest the brilliant book Power of Faerún, written by Ed Greenwood and Ed Boyd, if you want a whole books worth of ideas on how to play the political game, and set about bringing your PC's to power. You won't become ruler of Cormyr by teleporting into the throne room and slaying Alusair Obarskyr. Got to play the political game, finding allies etc. That seems far more interesting to me.
That said, if you wanted a game where you could come to power through personal might, just set the game in the Border Kingdoms. They are described in Power of Faerún as "The most favoured destination for adventurers who want to proudly and boldly conquer a realm or establish their own kingdom... Few folk go there except those who want to carve out a place for themselves with a sword." Sounds fun to me!