Mr.Gametheory says:
"The game play is too restricted. The Civ V dev team limits production, expansion, conquest, and strategic variety to make the game more competitive. However, this does a disservice to experienced players. For example, instead of making it so there is plenty of time to accomplish everything, there should be minimal time so players have to pick and choose how to spend their time. If the dev team wants to impose a limit, impose heavy penalties if players fail to build something in a city (city goes into anarchy for the following turn), players fail to perform an action with a unit that is not fortified (Unit can’t move the following turn), etc. By imposing these types of restrictions, players are limited by their own talents. By imposing these types of restrictions, they can lower the cost to build units and building, allow more cities on the board, and allow the games to go faster. I should not be penalized for building lots of cities or lots of units, however, these restrictions exist now to give newbs a better chance. Obviously this creates a more competitive league, but it also restricts pros from taking their skills to the limit. In civ IV, a duel could last 10 minutes, in Civ V the average time is an hour. They should be speeding things up."