In short : actually, in the tech tree, you have to click on the technology to see what kind of science packs are needed. My idea is to be able to toggle an option to show what kind of science packs are needed for each tecnhology not researched. This way, you can more easily choose which technology to research if you're short in X color science packs.
I made a visual example with my high skills in photomanipulation to help you to get the idea.
These are only illustration exemples of course, not accurate of real in-game science packs needed for each technologies etc... And it is simply for the idea : science packs can be (better) placed in other places, with more clear visual presentation etc...
And sorry if it has already has been discussed, I took a look but haven't found anything
[Koub] : fixed spoiler tags for you, they're tricky to use sometimes