I for one was not answering because we had some meetings about the future
Back to your questions, believe me, there is a purpose about the UI changes. You mention the leader outliner moved from right to left. At first, you can believe it has been moved just for the fun of it. But then you might recall that we have now these big round icons showing the most important messages of the turn, so that nobody miss them. And ... yes, they are on the right, because they are tied to the messages panel. So it explains why the outliner had to be moved
As for the 2-steps clicks, indeed it is because it declutter the interface plus allows adding some new buttons without having to redo the panels, as they are 'nested' as jack54 aptly says. You'll notice that the nested buttons have shortcuts though, and that for the map filters, they even stay 'opened' until you close them. Try A O D P for the 4 postures or shift A O D P for the ROEs.