Just to make sure I've got my mind wrapped around this...a hypothetical exercise!
If I wanted to eliminate the Training tech I would:
1. copy Techs_Amarian.xml, CoreWeapons.xml, CoreArmor.xml, CoreImprovements.xml, CoreUnits.xml, and TechTree_Amarians.xml into the My Games\Fallen Enchantress\Mods folder.
2. go into Techs_Amarian.xml and remove the Training techdef and the Training prereq from Weaponry, Drills, and Mounted Warfare.
3. go into CoreWeapons.xml and remove the Training prereq from Spear.
4. go into CoreArmor.xml and remove the Training prereq from WoodShield.
5. go into CoreImprovements.xml and remove the Training prereq from Barracks.
6. go into CoreUnits.xml and remove the Training prereq from Unit_Spearman_*.
7. go into TechTree_Amarian.xml and remove Training.
The game would then restructure the tech tree without the Training tech, correct? Everything Training unlocked would be available without research? Am I missing anything?