I used to think passives should not just affect enemy AI because then raiders would have an edge getting stats that help them beat the map while antagonists get no help.
Now after playing at high level MMR, I think passives are fine, but have them strictly affect enemy AI.
Introduce some new passives for the antagonist that buff all, or nearby, enemies. OR, make the antagonist get the same buffs that the raiders but, but have them apply to the raiders.
Make these stats like the forge system, where players get a set number of points (think any traditional RPG attributes) to either increase their resistance to shots, strikes, deal more melee damage, whatever. For antagonist have these trees be like...
-soldiers do more damage
-soldiers have more life
-Elites and bosses do more damage
-Elites and bosses have more life
-Add spawn rate +1, +2
-reduce respawn spawn timer, max of -5 seconds
And with a limited number of points, you could get a little bit of each, or pump up one or two categories. Some Forge skills take many points to move any number at all, like adding more bullets into your gun takes 4 points to add a single bullet for some guns, and stats like additional spawns or shorter respawns could work like that.
Allow these stats to be re-spec'd for a low faction point cost, like re-rolling cards. Maybe 3-6k.
