Actually an amazing speech my friend! I remember playing final fantasy XI and having a similar thing on the attack you mentioned! Hundreds of people at a time would join the "tower" in this case and protect it from a huge attack of enemies! There may be some copyright to fight for but I love the idea if that! Maybe of a weekend! But there has to be a reason for it! Like if we win and have control of the tower we earn more glimmer from killing enemies, but if we lose and one of the enemies, (Vex, Vandals, Kabal) control the tower then we earn less glimmer off of them when we kill them. Gives us a reason to fight for control! Maybe also add this to the different worlds. We can fight together for control of mars or Venus to gain extra glimmer off of enemies! Just an idea!?