I really enjoyed reading your post, and with so many bumps I'm sure bungie has noticed..... I feel like your onto something great with the defense of certain things from a certain horde that last several hours or maybe even super boss' attacking certain planets, kinda like an EVENT mission that broadcasts to all guardians like u mentioned, and could handle as many guardians as possible. I really feel though that to make this experience truly worth fighting for and winning, there should be something at stake for all guardians based possibly on the percentage of wins the entire destiny community achieved. Losing would result in possibly a reputation loss, or the designated planet the EVENT was on, if lost being blocked to guardians for a day or week. Another consequence could be xur not showing up due to the "war". Maybe even add destructible environments or altered environments if a loss occurs, like the tower being damaged or disheveled, filled with injured guardians "npc" of course. Things like that. Sorry I ranted lol......