I remember seeing a few people mention that the 'Chinese Civilization' is like a bubble, and that it would be more appropriate if its bonuses changed by era. The detachment of the 'Indian bubble' has been even more discussed around here.Also there has been discussion of something like that for a long time on the forums (usually as ways to make Modern Rome / Ancient America make sense as Italy/ AngloSaxon)
I also recall many saying it was quite absurd for civs like America and Brazil to start in the Ancient Era.
So it seems to me that the age system essentially solves these problem.