Hi Pip,
Just a thought. The civs that have military production buildings that work faster i.e. Goth Barracks, Huns Stable, Aztecs everything, should they not also research the technologies at that building 15 or 20% faster as well as create the units 20% faster?
I just looked at Husbandry, Tracking, Crossbowman etc and it doesn't say anything about certain civs researching them faster than normal yet you've done this for the Persians when they research any technology with their faster working TCs.
You're right about the speed increases of buildings, techs there do get researched faster. Not for Aztecs though, as their bonus specifically decreases the train time of units by 15% instead of making all buildings produce 15% faster