Domination of worlds by alliances and players who have already defeated the fortress.

I will have to strongly disagree. A game has a beginning and an ending. By allowing players/alliances to continue after defeating the fortress, leaving them to dominate and dictate the game play is not friendly, nor is it competitive. I am not saying they shouldn't be allowed to keep playing. However, at the conclusion of all great games, the player begins anew. What is the challenge in playing anew with a leveled player and a stacked deck?