To add to my two cents.... from a post back in february I wrote this:
There is something to be said for the strat of gaming the game... but how about a cool middle ground...
Velcro, Penicillin, Post it notes, Vulcanized Rubber, x-ray film, Superglue, LEDs, Teflon, and many many other things were all discovered on accident.
I understand that it is way to late to make massive changes to the game, but I would really like SOME element of surprise, or connectedness in the game. right now the research just feels dead. it is there but it is not interesting. it is like a necessary evil and not something that to me makes the game either more interesting or more fun.
The tech tree should be more intertwined and cross correlated. Researching in Military should open up options in Civics, Diplomacy should open up access to terror weapons etc etc etc. Right now the four areas do not link, and force a separation that is NOT found in real science.
I would also love there to be 200 or so Random just for fun "breakthroughs" that the player has a 0-20% chance or so of discovering at random. This would then give a bit of a wow factor. if they really wanted to add depth they could have a random breakthrough create a whole new chain.. you "discovered superglue" so it has a chain "Universal Cement" (faster build times on planet) and "universal Solvent" (faster mining) and "Laminar bonded armor" (better armor) etc etc etc..
I don't see the removal of choice or the burden of opportunity cost to be a bad thing. It is realistic. I think everyone has seen the Venn Diagram that has three circles, "Fast, Cheap, Quality: Pick one... Every day we choose to give up one thing to do another. However, in the game there should be SIGNIFICANT reason to do so. Be that via an expanded tech tree with mutually exclusive techs, or some really valuable bonuses that complement things.
Right now the "focus" techs are really just minor bonuses that stack up, but they are not cool they are not unique... they are as a commenter earlier said... minor bumps to slow down research rate.
If you want mutually exclusive Techs then why not have something like Primary Techs (techs that everyone always gets and have to go through to advance down the tree) Enhancement Techs (the current focus techs) These are sub branches, they do not need to be researched but give bonuses for doing so. Make each one much more expensvie than the last so if people want to hit them all they spend a lot of points on them. And then throw in the occasional unique techs that are truly unique. "Phasic shielding" "Temperal blink engines" or something that all three choices are cool and unique but are mutually exclusive in a way that if you research Blink Engines... you cannot have Phasic shields as they break and won't work.... Mater to Anti-Matter...
Again it is probably way to late to make these changes.... but the Game would benefit from them.