"I am unsure how I feel about this change. In practice, it almost feels like clicking the icon should take me to the front end of the site instead of the post management screen. At least with the WordPress icon, it felt like it was pointing toward an admin-side screen instead. For my workflow, I would rather see this link/icon replaced with a button that toggles between fullscreen and normal mode, popping the admin menu back into place rather than departing the editing screen altogether."

I completely agree. This change made no sense to me. Either put it back to the WP logo or change to a toggle fullscreen button.