The rotation would make people not get bored of the same tower, plus towers wouldn't have to be removed. A change in scenery gives players a reason to play during a certain rotation ("Oh I'm good at taking castle, sards, etc. I will tower during this rotation)

"A new season has started! Time to get my friends together and form a guild, We will break the 'most hours gained during a season' record."

Only 3 out of 6 towers would be used during each rotation, which would cause more guilds to fight over each tower. How is this not going to cause more competition?

I would have preferred weekly, but I think more people like for the towers to change every 3 months. I don't know, I get bored fast. Weekly to me would be more fun (fresh start, less camping)