The ability to research multiple techs at the same time: say three. Have a slider for each, separating them into percentages just like social, military, and overall research are. This way, if you want to research just one, you can. But, if you're a research oriented person or playing a technology oriented society, you could have more options.
I also think it would put more "oomph" on the feeling that you're actually going up in generations technologically, say, if you get Warp Drive, Phasors, and Medium Hulls at the same time.
