A public event for the tower called Siege you either defend or invade Let's call it siege where you defend the tower against a fallen, hive, cabal, vex or taken invasion, at random times it will show a prompt on your screen asking if you want to join the siege or not. If you decline it's business as usual, of you accept you will be spawned at the base of the tower with like 16 other guardian's you defended the tower and the longer it goes on the harder it gets it you succeed you get end game loot, if you fail it will put you in a last stand and you just clear the field and its over and you get ok loot just not end game light lvls. You can also reverse this and have a 16 man siege team invade a fallen, hive, cabal, vex or taken tower like base and you fight your way to the control center and if you make it you get loot end game loot, if all 16 people are dead at the same time you lose (like the nightfall before ttk(except you still get loot))and get loot based on how far you got. It will prompt the same as the tower defence one (your in the tower and it asks if you want to join a siege on the enemy base). This can be a end game like activity, similar to the weekly heroic and nightfall strikes you get high lvl drops for the first couple of runs then it will go to crucible or vanguard strike playlist drops. Also remove or reduce orbs, so there's no possibility of infinite supers.