In real wars when fighting occurs damage is dealt to infrastructure along with warring forces. I think linking a planet product to population as a percent of the base population would be intersting
Example: the base population is 100 with buildings the populations reaches300. The 200 % above base population would not increase production but if fighting lowered the population to 50 the result would be either a reduction in planet output or reversal of planet development bonus to the 60%
OR
Another way this could work is to make building require workers so you could scale population to mach employment [production =planetary output x (population/workers needed)] with the value of population/workers needed not to exceed 1

Mostly the damage to infrastructure is caused by the opposing force, in which in Galaxy Legion the only way that can happen is if you could see their planets. Though I like that idea as a way for declared war to have an actual impact on the opponent other than just kill count.

+1 this way war would actually mean something and take a toll on each side.

Not anymore than just taking their planets, though.

taking their planets hurts em, but the invasions dont always happen. this way when someone fails an invasion, the player would still take a hit.

I don't think that works, I think a better way would be [Production = planetary output x (current population / base planet population), again with the caveat that you can't get extra production by having extra workers

This way you don't have to deal with the question of "But if I have a small planet, I might not have the population to work my mines."

Plus it makes it easier if you don't add a new stat (workers) to buildings.

and wouldn't you also have to factor in buildings that add population? you can't really count that as part of the base planet population, and I agree, it needs to be scaled by type of planet and size somehow, but I'm not really good with equations...

good point

Actually you can already do this.
Invade an enemies planet. Now typically people expect to try and keep the planet, BUT, take it w/o the assumption of keeping it. Destroy everything on it, put some pop structures on it, but not defense. Now when they come to take it back, they have to burn the energy to take it, which is energy they arn't using to attack you, they have to invade it, more energy and at high levels this can cost BILLIONS of creds, then they have to rebuild the structures, again, billions more creds. THen the final clincher, another 5 days of waiting for the planet production to max out. Congrats you just accomplished what you were looking to do. Do this one planet it's a minor irritant. Do it a couple times with a planet it's realy gets irritating. DO it with several planets and you'll realy piss them off.