Well, setting a higher AI value just doesn't seem to cut it. I have the feeling that the duration a tech must be researched for, as well as the category it is placed in, can override the AI value for a tech.
So what I have done is to streamline the early Yor tech tree even more. For example:
New Propulsion Techniques, Ion Drive: Junked. Stellar Streams costs less to research and gives access to a Stream Drive. (Available after Efficiency Studies III.)
Xeno Communications, Universal Translator, Diplomatic Relations: When they figure out how to plead for us to stop killing them, then it's worth our while figuring out what to say back. (These technologies will be available to research after Space Weapons.)
Basic Miniaturisation: Seriously?! We have such a headstart on the other races as far as Miniaturisation goes, we don't need to bother with this right away. (This technology will be available to research after Space Weapons.)
Biological Studies, Soil Enhancement: Yes we really want to study the fleshbags and how they abuse their planets, after we have a plan to eradicate them. (These technologies will be available to research after Space Weapons.)
Technology Progression I on the Yor tech tree costs a bit less to research now because some of the technologies it used to unlock are now available after Space Weapons. The downside is that it only really leads to Extreme Colonisation and Collective Academies, that's it.