Biters could be a nice way to teach the player that it may not be the best idea to create pollution all over the place / map / planet.
From the biter perspective the player is the intruding alien that destroys their homes and poison their land. And if they try to fight the intruder off they get killed! What a massacre! This attitude of the game made me almost stop to playing it, as i consider this a massive problem which we all face in our own world!
I know that Factorio is about factory building and optimizing, but maybe it can also offer another optimization goal than "build bigger and faster"!
It would be great to support a play style where you still achieve your goal, but keep the environment (mostly) intact.
My way to cope with biters is to try to preserve as much as possible of the environment in order to contain the pollution cloud(s). This way the biters wont have to attack my installations.
As the biters expand (if you don't turn it off) there is a constant thread from them until you have a working perimeter defense to keep the expansion parties at bay.
Thus my factory will (most likely) be tiny against other players setups and i still do kill a lot of biters (mainly on mining outposts), but i think that i will also get my rocket into space.
I think that the biters aggressiveness should increase with the amount of pollution they absorb. Currently the biters just evolve faster if they absorb pollution, so it becomes harder to fight them. But as far as i've seen it does not change their behavior.
- In the beginning the biters could be neutral against the player and it's installations.
- They become more aggressive when they have to absorb pollution.
- They could start to attack even passive structures (power poles, rails, etc.) if the pollution is too high.
- The attacks should reduce again when the pollution reduces.
I really like the engineering aspect of the game, but a bit of lore would be nice too. The game has the potential to give such feedback to the player.
And if a player don't like it and want to focus on building, they can turn off biters.