Map has a ton of influence here, obviously.
on an Astro map, it is clearly the most important. Otherwise more left up to your gambit in that game.
not Liberalism. It has little value in itself and is only used to shortcut...usually one of these other techs, haha. Can be great trade bait for a long time, but if you in the Lib race....it's like, a terrible tech to spend effort toward.
Nationalism is too specific. MilTrad too.
Rifling is more a necessity tech to me like Gunpowder, just later and more of a pain to detour if you aren't already planning to exploit Rifles...I most often only pick it up when I recognize I'll need Cavs to finish out a game or when moving on beyond the eras of mounted combat because I couldn't end it. Huge impact, but you can plan the game around undermining it before it shows up...and after a point, it's just required for anything approaching Industrial/Modern.
I don't know. I went for Education for it being a pivot into Gunpowder and Lib which makes it quite important in many cases. Being easily bulbable, great for trading, and also leading to fluff like Economics (I mean, if you are really ahead, might as well try for the GM or the Free Market early) certainly helps its case too.