Someone mentioned earlier that you shouldn't be allowed to trade/conquer/steal techs that you don't have the previous techs for. I totally agree with that. This is the way it's done in Civilization and it works well. I think this alone would go a long way to fixing the tech trading issue. You'd only have so many techs you could trade for at any one time, so you couldn't jump ahead of your current knowledge base.
i don't agree. Tech trading should be free as it is. It's already very intricate to trade techs that i can't imagine myself in front of the diplomacy screen bargaining for hours for basic techs and weak weapons. In civ many techs (particularly in the beginning) need the knowledge of previous techs to work (how can you build cannons if you don't know how to deal with iron?), in GC the situation is completely different and i think you're able to understand for example plasma weapons even if you don't know laser I.
maybe it would be great if, when you trade/steal/conquest a superior tech, previous techs disappear from the diplomacy screen (except for that previous techs that give to you cumulative bonuses like diplomatic and planetary invasion techs). But again, also in this case i have doubts. In fact sometimes you could mass more weapons with a previous weapon tech than with the new (bigger) one.
Instead, it came in my mind something i haven't seen in this topic and appeared in solver's review at apolyton. I quote:
Please, for the sake of what little is left of my sanity, have a “maximum they’ll pay” button for gold. I realize there’s are many combinations of what the AI would be willing to pay, but a button that fills in the maximum amount of gold – and gold only – is extremely straightforward and would certainly save lots and lots of tedious clicking to find just the right amount.
richard