Percent Bonuses Should Be Logarithmic, not Linear

But in what way is this realistic?

Also it seems your system would result in multiplying the value of population pretty intensely, making invasion a completely loser strat until almost all of known space has been claimed and developed.

Diminishing returns.  

On maps with lots of planets, invasion IS a loser strat until almost all of the worlds are developed.  

Before your suggested change did you mean?  I think that might be the real problem.  When you view the game as us versus x copies of us (but not as good-looking, naturally) then there's some point to the planetary takeover mechanic, but we're supposed to see it as every player growing their civ organically, deciding crucially about strategically situated planets.  Only in multiplayer would that be remotely possible - in that case your statement does not apply before your change, and it's closer to being applicable with it as I've already stated.

yeah I'm mega-against turning solo gc3 into a bureucrat's wetdream which is what this finagling seems to be taking it toward.  would you say that people have a good instinct for working within your alternative system?  I'd say it's steepening the learning curve instead.  yet, to move in the opposite direction would entail creating realistic interaction by the AI.  why not make their simulated emotions logarithmic, as long as we're talkin number theory?

I will admit I feel after 2.5 games played, that starbase benefits should be logarithmic.  or else their cost should be made exponential, somehow.  let them justify it however they like, I don't care

On insane maps I am regularly at war before 20% of the map is revealed. I will often have an AI DOW me and I will be put on the defensive till I get PI. Invasions will get MUCH harder once Stardock gets to looking at it. Currently resistance does not do much nor does planetary defense. However, this will change likely next month. You will need to get invasion techs and the AI will defend MUCH better than it currently does. 

No do not change the way the bonuses are applied. Specialization of planets is one of the ways to beat the ai which will be required as we move forward with progressively better AI. 

That Elerium shield thingie begs to differ. 100%+ resistance is no joke to invade It always annoy the crap out of me when one of the AI's decide to build that thing. 

Defense is overpowered; resistance is largely pointless. Defense kills that % of the invaders before they can do anything. Resistance neer builds up enough power to cancel out the population division.

I am still badly out-expanding the AI on suicidal with Naselus's IAB mod.  Of course that's partly because I know almost every trick in the book when it comes to expansion.  

You already get diminishing returns.  

Only in the beginning. In the late game God knows what I can produce.  

But I've found this to be the problem/benefit (depending on how one sees it) of every 4x type game I've played.

Unless one somehow hamstring ones race (deliberatly or by accident) by the time one is at the '...end of the manufacturing type techs...' stage then any half decent planet/state/constrution ship etc will be able to knock out endgame type weapons/ships/structures in a silly-short ammount of time.

The only way to change this is to have some kind of penalty (like the one marigoldran is suggesting) but then it effects the game too early and becomes a teeth-grinder, or 'cuts in' for no real reason and becomes immersion breaking.

This and Time to Research Techs are the two things that take the most balencing but are the two things that are always in these sorts of games and no one seems to have got it really right.

Naselus is nerfing adjacency bonuses massively.  Which is a pretty good idea.