I think the idea between the fast science + longer production + limited districts/population was to make it even more a game where you couldn't "build everything" and had to be very selective with the choices you were making for the victory type you were aiming for (versus just being able to build a powerful 'balanced' empire and win whatever condition you like).
I don't think they exactly hit the mark with this (especially with the mass city-spamming essentially leading to a powerful empire), but I think that was one of the intentions, game design wise.
