Vanila tech tree was around for such a long time, that one can say it withstood the test of time. Why fix something that was not broken? OR really allowed for some flexibility and DECISIONS, which is always fun, AND takes away that fun
If anything HR has
another tech tree, not a better one, certainly not the best possible one! While it feels more historical in some instances it becomes less historical in others. Take Alphabet and Writing in vanila for example. Chinese never developed Alphabet, but using OR allows them to go pretty far in tech tree without ever needing to research Alphabet. Or think about Wheel and pre-Columbian. OR allows to do Construction without Wheel, but with HR tech tree that will no longer be possible. History in general has more OR feel than AND anyway.
Writing firmly belongs to ancient era, not classical (literature belongs to classical if anything). You already need to know writing of some form to keep records, or create a calendar. Plumbing and Sanitation sound very much alike, and yet they are separated by 2 eras, did Harappa have plumbing or sanitation? Or both? Metallurgy needs Chemistry more than Physics. Why would Bombards come before Muskets? Gunships do not belong to digital era. Development of Chemistry preceded development of Biology. National Gallery fits Heritage better than Civil Liberties. Etc, etc, etc. I can't even imagine how much rebalancing would be required for the mod with UHVs, such as "discover entire tech tree" or be first to build, etc -- we did spend so much time adjusting everything to the existing tree.
In short -- I pity all that energy, time and work which will go into this overhaul. Nothing in this new tech tree is too exciting in my opinion. Internal logic is at best debatable -- I really cannot image for the core players of this mod to look forward to this big blow to the existing balance, which was polished and fine tuned for years now. If one can imagine 3 dimensions in any mod -- length, width and depth, I think DoC is fine in width and length dimensions and at this stage can afford to focus on depth only. But now we will be facing width and length adjustments after all this years of fine tuning...