Well, I certainly haven't modded it myself yet, but I'm intending to work out a system that paces a sort of "world tech." Basically, during the early game (I would set a cutoff around Education or Printing Press) technology research is somewhat limited, somewhat shared between civs.
So, all civs would have to set the slider somewhere between 20% and 80%, the premise being ancient societies are not very effecient at allocating the general "commerce" resource - you can't spend everything on research, or everything into gold. This would also encourage more use of gold/espionage in the early game, also less "deficit" teching. Then, half of this slider (technically, half of total beakers produced in case you're getting them elsewhere...) would apply to the civilization's own, individual research. However, LIGHTBULBS go to ONLY your own research - for a balancing emphasis on specialists. Representation no longer gives +3 beakers, instead I would give Rep a maintenance bonus (I'd be modding other civics too, State Property would probably lose this bonus for something else). always thought the pyramids were broken - later in the game some tech will unlock specialists giving more beakers.
So, what about the rest of the beakers - well, they go into a something like a "world bank". More specifically, for every civ you have contact with, this research is split and applied to techs among all civs. World technology researches techs in a mostly pre-specified order (I think some variations game to game would be cool). For instance, the first "world tech" to be researched would be the wheel - but if a civ already has this it goes to the next on the list. If it was to vary game to game, the level of tech shoud be kept the same (So, in a different game, a random seed decides mining is the first world tech-then the wheel, and so on). Obviously world tech ends at Edu/PP whatever the limit is - after this a civ's own tech is entirely there own (BUT, they still get world tech from the OTHER civs, until these other civs obselete it as well). You could even move back the mercantilism civic for an early instance of this - a civ that purposely isolates itself to keep its own researches but not share in others.
How would this affect the game, though?- That's the main goal I am looking for. For one, tech in ancient times would be both more even and more guarded between players. If any civ has a massive lead in commerce, some of this will diffuse into world tech for other civs. Playing an isolated start has even more of an effect, because no contact with anyone else means world tech has no effect on you. However, specialists would likewise become more important (but not pyramidsSE broken) because bulbs are not shared with anyone - these early monopoly techs could be crucial. This system would also end a lot of problems that exist with WFYABTA because early backfill techs are achieved through world tech, rather than more trading. And remember, there is of course still incentive to have more research because you're never behind another civ (you still get half of your beakers towards whatever you want, some share of their beakers to you, and you and choose your own techpath) as worldtech will almost always be more backfill.
This would also require retooling of the AI (one of the main reasons I haven't modded it and other things yet, cause I'm just not ready to handle all that). But I think it would give an appropriate use for more stinginess/monopolizing on early trades, also, achieving a certain tech advantage would be even more effective if you're the only one with it. I would also be sure to allow great people to have a choice between techs to bulb (if at all reasonable) instead of having to bulb a certain tech, to allow this flexibility. And again, this concept of "world tech" allows more focus on espionage (stealing away monopoly techs) and other uses of gold (I think some things on the upgrade/pay rush system should be modded too.)
Finally, to respond to some of the other suggestions, I don't like blind research, and research for a very specific purpose is lost in civ. For instance, many scenarios do have a use for researches like "upgrade gunpowder weapons" but for the general civ game, you'd have to massively slow it down for these techs to be used. In various mods/scenarios they make more sense, but the progression through the tech tree has to be emphasized in the main game. The only exception is I think is diversifying final SpaceShip parts that each have their own, future tech (The tech only allows building a special part - say, researching solar sail allows this part which speeds up your ship, but that's all it does).
