Bring Invasion back and use it to keep Allflame monsters in the core game

As of sextants being removed from the game in 3.24, invasion is officially gone from the game.
(I see you, Invasive Adversaries)
But what if it were slightly reworked and added to the core game as a way to keep Allflames? Sure, I'm getting ahead of myself, but let's assume for this discussion that Necropolis isn't going core.

My pitch is that you get a few clusters on the atlas tree that give you a chance to get invasion in your map. Then you have nodes that give a chance for the invasion to replace monsters in your map, and nodes that have a chance to replace the boss.

The monsters and bosses could be old or side content like the current allflames: Karui, Wildwood, frogs, Synthesis, rolling fucking money, rats, etc.