Seems like an intended change to me.
If it's intended, then it's an ill-conceived change.
On pre-Sequoia systems I could double-click the title bar to minimize the window, and option-green to zoom.
What's the point now to have BOTH actions to do the same? Not to mention that it breaks established actions that users have used for many years.
But I think Apple just forgot about the option-green click. They added a new item - Fill - to the menu, therefore certain numeric indexes related to this feature have changed under the hood. The option-green click simply keeps using the old pre-Sequoia value, whose corresponding action has now changed. (Just my guess, of course).