I've got some ideas that I am starting to kick around and see what is possible. I want to finish this whole graphics rework before I start posting them.
The biggest issue is sheer numbers of techs. The pre-Industrial eras currently split 37-29-29-35. The Ancient Era gets more techs because it mixes a few Stone Age concepts (Ceremonial Burial, Naturopathy) along with the Bronze Age.
The Industrial and later eras have counts of 55-45-52, after removing Romanticism, Realism, Computer Networks, and Wearable Computers. It's been so long since I proposed getting rid of those techs that I'm totally used to them being gone. Trying to get down to 40 per era would mean chopping out 32 techs total. I don't know if that is possible, but I plan to try. I think it will mean gutting the Industrial Era and rebuilding it from the skeleton.
I see at least one possibility for shifting techs backwards from the Transhuman to the Modern (Automated Traffic), but I don't see any chance of shifting from the Industrial to the Renaissance. I think it's appropriate to use a timeline to place techs in the Renaissance era and later because that is when Western Europe starts to really set the technological pace. The last column of the Renaissance Era is the technologies of the Napoleonic Wars; Grand War and Military Tradition are here, and so is Democracy, which is taking off in the USA at least. The only technologies that I have dated to pre-1815 are Steam Power and Assembly Line, and these are so iconic to the Industrial Era that I cannot justify moving them backwards.