User blog comment:Equillibrium/Elder Scrolls Online Gets Graphic Overhaul/@comment-13446185-20130926220112/@comment-3076045-20130930133428

"I know you were probably joking, but the rules for how you can name your character in ESO mean that you'll never see a name with numbers, random capitalization, or three of the same letters in a row."

Poor Jimeee. ;)

As to the actual question, the reason for this is that it gives the factions something to strive for. You become emporer, your faction ABSOLUTELY dominates. And you can keep it even after a different faction takes back a keep.

Its also worth noting that you have to control EVERY keep surrounding the Imperial City. During every beta test, noone has managed to get Emporer yet - it is literally that difficult to obtain it.