I've been thinking- several techs I just flat-out don't use, even situationally. It's like the choice is so bad it doesn't exist.
Idea: make several techs a function of the overall tech level, instead of actual techs
How it would work for each branch I think
Diplomacy: I don't know. Maybe a static defense bonus to caravans/DC bonus/trade bonus?
Adventure: maybe heroes should be spawned this way, the more emphasis you put on adventuring, the more adventurers you get?
Warfare: several passive things like peasant levies to defend towns, maybe experience levels, maybe even the stuff everyone uses (to discourage beelining)
Civilization: maybe buildings could be unlocked this way.
Magic: spellbooks open at random based on x number of levels.
The way the tech tree is setup in Elemental, it only really works if there is a tough choice. Oftentimes, the choices aren't particularly tough- some techs are just 100% vital, even first, and some techs aren't even situationally useful. Those are the types of techs that shouldn't really be choices, but granted at x level.
I do think some of this should be random, and some should be just based on x lvl.