Outside of tweaking the tech tree and combat and general intelligence(spying) bonuses I would really like to see evolving 'knowledge' of the other civs during a game based on your experience with them in addition to the tech tree. I also like the different weapon type options proposed for GC2 but would like to see a factor that depends on how much combat you have had and what the reult was.
I would like to be able to gain experience 'globally' from interacting with the other civs either positive or negative effects. Therefore, when we first meet a Civ we should have ZERO knowlege of their capabailities or strenghts or weaknesses or alignment. When we first encounter a ship we should be able to determine if it is eg. A colony ship/trader/science/combat vessel etc but not know their stenghts at all or maybe not be able to identify the class. (think in WW2 when sub commaders had silouettes of enemy Japansese ship from intelligence so that they knew what it was. But an alien ship....?)
Likewise we should not know what tech they may have or their overall strength at the beginning - how could we...or they? This should only come with either battle experience/ intelligence?diplomacy etc.
To this extent I would like to see knowledge of their capabilites and relative strenghts appear with time. This should also be factored in how they deal with us. I think this could work by having an additional bonus (+ or -) based on previous battles/interaction with that race. Eg. If we lost our first encounter we may then have a negitave bonus on our next one due to fear/reputation/unknown technology etc. This would mean that our ability to combat different Races will depend on our overall knowledge and experience of that race. So we may get a plus bonus against civ X and negative one against civ Y.
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From a cultural aspect I think we should be able to get +/- bonuses based also on our trade and our relationship status as well as intelligence. How about being able to put an embassy on one their worlds like we do here in foreign counties boosting trade and cultural influence and knowledge? If another Civ gets Battleship Tech we should not necessarily know they have it unless it is in their interest or we have 'discovered' it.
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Another idea (maybe already voiced). Is that we could have military academies to improve our crew skills helping in tactics etc also effecting bonuses.
Also if we have new ship or military technolgies eg advanced weapons/shields we may need to completly build or rebuild shipyards manufscturing areas before we can implement the new technologies. Leaving the decision: Do I mass produce Ship X or trash Ship X facilities and then build a new plant for Advanced ship Y?
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I am not thinking that any of this might turn up in any version of the game, but this emulates how it works in our real world nationally or what I think may happen if we really did contact aliens. What I do hope is that this might get some folks thinking of other ideas which could improve the depth and variation of the game while still sticking close to the current features..