This reads like sometimes the ideologies are being evaluated based on their descriptions. Unfortunately the game doesn't have reliable descriptions and it requires both parsing the XML files and ingame experimentation to find out what everything does.
I'll discuss the Progressivism tree since I've recently finished a game where I completed it.
- Eureka: I agree about the stackable bonus being great. Personally I like the first option being this good and potentially worth splashing so I wouldn't change it too much. Perhaps the 6th stack should remove the oldest one so there's a maximum of 5 stacks at once. (Duration is 10 turns btw.)
- Deep Investigation: Relies too much on early "new anomalies" being good when actually your flagships are probably still busy with old ones for quite a while, and tech tree offers them multiple times later.
- Innovation: Innovation Complex is good for boosting other research improvements.
- Early Adoption: very random benefit based on which techs you get offered at discount
- Breakthrough: Hyperion Shrinker is nice. Somewhat high build cost of 600 manufacturing and 5 prom. For anyone who doesn't know, building it helps fit more stuff on your ships and you can get it relatively early.
- Risk Taking: The description mostly fails here. Most importantly this unlocks the Think Tank improvement (civ achi) which gives raw +1 Research per level. It is a centerpiece of your research world. The Shark Tank is also a good econ building with adjacency bonuses to both wealth and research, so it helps tie those improvement groups together. This is the best reason to go beyond first step into the tree.
- Futurist: Possibility Engine is a massive 50%+5%/lvl research bonus but you probably have a bonus in the hundreds on the planet already and the 2400 build cost may not always feel worth it.
- Quantum Leap: Game tends to hide research costs too much but if you compare to core world production, 1000 research probably won't excite anyone at this point.
- Singularity: Bugged? The description oversells it in the first place. From XML file I would expect +1 intelligence for all citizens and leaders but I didn't see the modifier appear. (And it wouldn't be amazing compared to Genetic Manipulation policy.) For some reason I saw a super minimal +2.60% to +2.80% effect appear per core world, instead. The expensive tech option showed up but haven't tried it.
I won't try to make this comprehensive since I need more practical experimentation and the XML files are so annoying too. Couple other things I want to mention.
Traditionalism T1, Sacred History
Hall of Tradition gives +1 Culture per turn, +1 raw research, and a minor +1% gross income per level. Original post valued it at C. But any ideology tree path will quickly catch up by taking this first, compared to not taking it. If you can get Hall of Tradition built immediately, reaching your 4th ideology trait can be faster than reaching 3rd without it. From there the advantage keeps growing. The last T6 trait of a non-traditionalism tree can be reached up to 31% faster by taking this first. Calculation ignores one-time Culture rewards and ideology discounts, but the latter doesn't change things much. Other sources of culture per turn would reduce the relative advantage.
The reason to not take this first is simply because we value something other than Ideology traits. For example, getting those early colony ships, approval bonuses or constructors from other trees ASAP. Or rushing some slightly deeper trait without having the 1 promethion for the Hall. After taking multiple other traits due to their urgency, detour into Sacred History is only a very long term play.
Traditionalism T5, Devotion
This takes the cake for most misleading description I've spotted.
Description: "Every citizen with the traditional trait produces +1 raw minerals per turn for their core world."
From the XML, actual effect appears to be +2 Control per turn, and all current and future Leaders get traditionalism trait. I still need to find an opportunity to try this in practice.