I'm also really upset at the maximize button change, and someone suggested today that instead of fiddling with the button itself, there's a [free mac app called "spectacle" that has a bunch of handy window management shortcuts.][1] 

It has cmd+option+F for full screen, and a bunch of options for 1/2 screen, 1/3 screen, top half, bottom half, etc.

![enter image description here][2]


  [1]: http://spectacleapp.com/
  [2]: https://i.sstatic.net/vke8O.png