After the long work trying to bring the game to a whole new level, Age of Empires Patch 5.1 will offer a lot of new changes in order to improve the gameplay experience.
The Devs have been monitoring the forums and noted what kind of fixes should be deployed.
This 5.1 patch should definitely offer a lot, just as it was noted.
However, this is not the end, meaning there will be more fixes that are planned to come in near future.
They also noted that the 5.2 patch will include AI improvements and Multiplayer optimization.
If you want to see more detailed info of the patch notes, visit this link.