I think it would be a neat risk-reward addition to temporarily debuff the evolution factor (to a limit) based on the number of enemy bases or maybe even enemy units killed in a given time span. Not sure if factorio does this but if you can track whether it was the player doing the killing or not that would be best- automated defenses shouldn't have any factor in this, only the player's direct actions. This would give the player a way to alleviate pressure on their defenses in situations where the evolution factor ticks up a bit too high to contend with the higher-tier enemies spawning as constant assaults. It would probably have to last a few hours; though ideally a config for decay factor and such would be best since people play at wildly different timescales and the mod is already amazingly configurable (really appreciate that!). I've done a few runs with Rampant (fixed) and there's always this oscillation between doomed timeline or not when the AI state changes and I'm not quite ready for it. In many ways, that's part of what I love about the mod (I mean obviously I want the enemies to be a challenge, why else would I be using it?) but at the same time factorio is a marathon so it feels really bad when there's also not any obvious paths to get yourself out of the ditch if you end up behind the enemy scaling. I find myself flitting between defensive lines, shoring up holes and stopping large groups, and then get a second to think and realize I've not actually progressed the base for multiple hours and I've run out of ammo because I couldn't finish building my rail line 2 hours ago. This is especially true when accounting for the points they get from you destroying bases (afaik) along with the sheer alert distance when nearby one (causing enemy groups to be sent from bases that are at least 400 meters out from the base you're attacking).
There's actually already a mod that does this sort of thing but it seems like it permanently lowers the evo factor which just means there'd be some tipping point in combat-effectiveness where you cascade into bringing them down to the minimum evo again. That's why I think it should only be a temporary effect. Make it just long enough to get some things done in the base without everything exploding and then hopefully by the time the debuff clears you've managed to get some better ammo or tech.
Something else occurs to me in that maybe this could be tied to a consumable like the current combat powerup. The only issue is that would make it kind of inconsistent (since you'd need the drop). Though I suppose the existing powerup itself is kind of a tool for this already but the issue is you have to actively defend using it which means you can't be building the base and also you can't defend multiple fronts in the mid-game that way, especially since it doesn't seem to affect vehicle weapons at all.
