Wow very impressed with the community spirit for this game! its very deserving as it is a brilliant at what it does, but yer back on point. I completely understand how it could well become very difficult for any machine to be able to process a large map size with each city having over a 1000 full generated citizens in late game. I have come to the conclusion that city growth is pretty much already optimized to the best of anyones ability to allow the game to run of most peoples gaming machines in late game, anymore and it would become a laggy mess even when graphics are not loading in.
However as this limitations cannot be overcome easily , in my personal opinion i cant speak for anyone else, I would like for the goods requirement for towns/cities to increase as this would allow for much more flexibility for freight networks and would make the game more fun and challenging for me to try and deal with the logistical nightmare that might be trying to send a fleet of goods trucks through a crowded city with trains, trams and buses.
Thank you for all the responses!