Liberating civ bug

In the base and 1st expansion to Civ V god of war, you could liberate countries from opponents,

However, the fun and usefulness of doing this is negated by the fact that they remain at the same tech level as they were before being conquared

for example, if the English were conquered in the medieval era and I liberated them in the atomic/modern era, they would still only have medieval era technology

this is a major flaw in my opinion to the game, particularly for players who don't wish to vastly expand their empires and preference diplomatic or other types of victories.

So, what if liberated countries received the same tech tree as their liberators or at minimum some of the techs dependant on how backward they are to the rest of the world???
I don't want to always conquer large swaths of the world, its been a constant problem in most civ games I played in the past.
has anyone else experienced this? also, do you think this or a different type of change is required to improve this aspect of the new Civ V expansions gameplay

 

I think a bigger problem about liberating civs is the diplomacy. I remember when I liberated Egypt and I asked them for a defensive pact, so they don't get attacked by their neighbours again... they refused and even denounced me next turn. Several turns later, they were conquered back.

So why should they refuse a defensive pact with a powerful civ ? Especially after they got liberated by it ... !? That''s stupid. I had the most powerful military force in the game and I offered protection...

 

that diplomacy aspect is pretty important aswell but then whats the point of liberating another country in the game if they can't defend themselves from their backward technology.

generally I manage to become allies of liberated AI but they become more of a burden from their lack of modern technology during times of war. unless they get the same or at least relatively close technological potential to their liberators, then theres no point of liberating them in the first place.