Prior to the redesign the bottom bar comfortably housed all the necessary actions, including the Preview button. This button is arguably the most important button in the GUI, as the WYSIWYG editor doesn't always produce the desired results.

On a personal level, I would say that the people who came up with the new button placement, approved it, and implemented it never ever used Confluence for any extended period of time. It's a change for the change's sake, as I can't imagine anyone look at the ~1500px of empty horizontal space and say: "it's not enough to place three or four buttons there. Let's only show two and hide the other two behind a drop-down menu".

Even if you argue for a mobile look, hardly anyone edits Confluence pages on the mobile. And even if they do, there' s plenty of space even in the mobile view if you remove/shorten the otherwise unnecessarily long "Latest changes have been saved".

Original Tweet: "I do realize that there's just not too much space at the bottom of the screen, but perhaps, just perhaps, hear me out, you could possibly not hide the extremely useful "preview" button in a totally useless two-item menu?" (https://twitter.com/dmitriid/statuses/1076027320316674048))