If you could make radical changes to the game, which would those be?

Just for entertaining purposes, I'm curious: What mechanics would you guys completely change/remove or add into the game if you could...

For me, I would be:

• Make Towers do more damage when near a Town Center or a Castle.

• Create a "late-game" upgrade building like AoE3's Capitol (one of the things I really like about that game)

• Make tree stumps regrow within 30 minutes of ingame time if nothing is built upon them.

• Increase the resource capacity of gold mines from 800 to 1100 and stone from 350 to 550.

• Being able to Trade with your own markets at a huge gold penalty.