Advisor Unique research?

I'm loving and enjoying this game so far. Pretty much in the process of maxing out all the civs that are available.
So i'm thinking with Advisor Unique researches, something like an age 3 legendary advisor that provides a unique research or unique research chain like in Age of Empires 2 that provides additional bonuses to civilizations. The Unique research would be researched at the fortress and can provide very unique stats that aren't straight increases in HP, movement or attack. So for example:

'remove gold cost for a specific unit but increase its alternate resource costs'

'substantially increase transport resource and pop cost but allow for ranged units and siege to fire out of transports'

'Age IV unique unit can now be trained at barracks'

Anyways, keep up the good work.