A caution, based on my own recent misadventures:
Anyone looking to suggest a change--and still more, to suggest an implementation of the change--has to remember that the player's in-game experience is far more important than the underlying technical models. I'm not talking about interfaces like keeping or abolishing city-view screens (those are cosmetic features that have changed quite a bit over the years). I mean that you need to keep track of how the player interprets his experience while playing the game.
In my case, for instance, I wanted to change the player's experience by coming up with some way that would license a much richer array of alternative techs and units than the game currently allows. The idea was that a new technical way of modeling techs would make them more "modular" and easier to connect with each other so as to create novel units; the process of creating techs could be partially realized in a new version of Civ and easily expanded by the mod community. It turns out, however, that the model I proposed was functionally equivalent to the system already in the game, so that 90% of what I wanted to do can already be done by a clever modder. So, if you're going to come up with a new system, you need to be sure that you're not just reinventing something that is already possible and that the designers have left to the modding community to exploit.
Alternately, you need to watch out for ideas that, in practice, might simply recreate the current in-game feel. I worry something like this might happen with ChrTh's idea. He wants there to be a real difference between "discovering" a tech (in the sense that a civ can pick it up and play with it) and "adopting" a tech (in the sense that a civ can actually start using it). There is more going on with his idea, which is good, because I doubt this elementary change would be enough: the process of "discovering and then adopting" by itself seems indistinguishable from the current game's "finding in the research queue and then discovering" process.
Anyone looking to suggest a change--and still more, to suggest an implementation of the change--has to remember that the player's in-game experience is far more important than the underlying technical models. I'm not talking about interfaces like keeping or abolishing city-view screens (those are cosmetic features that have changed quite a bit over the years). I mean that you need to keep track of how the player interprets his experience while playing the game.
In my case, for instance, I wanted to change the player's experience by coming up with some way that would license a much richer array of alternative techs and units than the game currently allows. The idea was that a new technical way of modeling techs would make them more "modular" and easier to connect with each other so as to create novel units; the process of creating techs could be partially realized in a new version of Civ and easily expanded by the mod community. It turns out, however, that the model I proposed was functionally equivalent to the system already in the game, so that 90% of what I wanted to do can already be done by a clever modder. So, if you're going to come up with a new system, you need to be sure that you're not just reinventing something that is already possible and that the designers have left to the modding community to exploit.
Alternately, you need to watch out for ideas that, in practice, might simply recreate the current in-game feel. I worry something like this might happen with ChrTh's idea. He wants there to be a real difference between "discovering" a tech (in the sense that a civ can pick it up and play with it) and "adopting" a tech (in the sense that a civ can actually start using it). There is more going on with his idea, which is good, because I doubt this elementary change would be enough: the process of "discovering and then adopting" by itself seems indistinguishable from the current game's "finding in the research queue and then discovering" process.