one oversight in the civ series is that hind sight is always 20/20, and we all know how history has progressed up until now. however, no one in 1900 thought "ok now that we have combustion and replaceable parts, it's time to develop tanks". if ww1 didn't happen, we might have discovered flight way before motorized transportation. since the name of the game is civilization, and not "history", it's kind of senseless to have a predesigned tech tree that everyone follows. to improve the existing system, this is something completely new i'm proposing: event-based technology development system (EBTDS)
not all civs continually developed techs through out history. certain events and conditions trigger new technologies:
historical examples:
1. tanks were developed in ww1 after huge casualties in trench warfare was experienced. translation to game - a civ would have a chance to develop tanks after some prolonged infantry warfare. nations that weren't involved in that war would not spontaneously discover armored warfare. historically, nations that weren't involved in ww1 didn't begin tank development (and never thought about it seriously) until after the war was over and until they had observed the effectiveness of tanks.
2. the newtons or baches in history usually had the proper environment to develop intellectually. a peaceful, high-cultured civ with good infrastructure will be much more likely to sprout great scientists and artists, who in turn endow the civ with great benefits such as wonders or technologies. translation to game - a constantly warring state has a very low chance of advancing their technology in theoritical science and art, which provide the foundation for applied science. making peaceful development time necessary. tech cost will be significantly modified by existing conditions in a civ.
so in essence, under EBTDS technology is triggered by the player's actions, and supported by the player's funds. this dynamic system allows each civ to develop slightly different techs under different circumstances. the aim is not historical accuracy (since the game is not "history"), but accurate tech development and realistic tech leads. everyone can START research AFTER one civ has COMPLETED its own, as they would then have something to copy from. but combine the research with resouces and you can have a truly interactive system.
game example: since france has been at peace for 100+ years and it has good infrastructre, a great scientist (let's call him x) has discovered the principle of fission, a theoretical advancement. france can now see uranium on the map. from this point on, other civs can start reserching fission too, as they have heard about the discovery. suddenly a world war breaks out, and germany is looking to develop the atomic bomb, an applied science advancement. however, in order to efficiently research atomic bomb, germany needs uranium, which it doesn't have. therefore it must research at a much reduced rate. at the same time, the americans, who have used towed artillery extensively in the war, now have the option to research self propelled artillery. and the japanese is now able to research aircraft carrier because it has a sizeable navy and air force... etc.
obviously technology cannot be sold for 50 gold under this system. techs are actually precious here, just like in real world. and being the first to meet research conditions is very advantageous because others cannot start until you finish (unless they also meet the condition, of course)
so there you go. no messy micromanagement, and a different tech development pattern every game!