it seems that it would solve multiple problems
-civ techs being the best choice for a long part of the game
-city growing too fast and with the new level up bonus its a bit too much
-making things improving growth a factor, right now you would NEVER enchant a city with growth or value a champion providing growth
after reading others opinions i changed slightly into
-moving prestige from first techs to other later techs
-others suggested later techs should provide more than 1
-consulates makes not much sense, the bonus could be moved into something else helping improving growth on demand late game if your empire need it