One thing I know is for sure is why they haven't yet given a tool to create new worlds for the player ` EA knows nobody would want to buy a DLC for a new world, when the fanbase knows simmers are more creative and talented and would prefer downloading something for free with the outstanding breathtaking scenery. As for not giving us a tool to add, change and remove lots: it's they're lost really. Can't come with an conclusion why they haven't release one yet. Is it really engine/budget to blame here?
Wild guessing, but Newcrest could have been just an exception for the players to gain a wee bit of their trust due to the negative reputation they get everytime for dump and poor choices they made, and the lack of respect they show/provide to their fanbase.