As written below the most recent windows phone 10 preview introduced many design changes. While the OS is really far from final, the design changes at least show in which direction MS is going with windows phone.
Of course it’s my personal opinion but I do not like these „androidification“ of windows phone. 🙁
More details about this design change can be read here: http://www.windowscentral.com/why-microsoft-hamburger-menus-windows-10-phone
„Windows Phone’s original interaction model put actions on the bottom and navigation on the sides, as swipes. That’s not a great pattern for a variety of reasons.“
Really? Copying android was the best design idea you had? I disagree with MS and everyone that has tried to use the new UI will disagree too, please read: http://wmpoweruser.com/why-a-two-hand-ui-does-not-make-sense-even-on-a-two-hand-phone/
If you want to test the „new UI“ and do not have a phone running windows phone 10, you can try the MS health app. It also works without MS band and you can try out the new UI yourself.
I liked the new, clean approach MS took with metro style, panorama controls and a menu that was easy to use with one hand. If this all will be changed windows phone is no longer different from android and the obvious question arises: Why use windows phone when it looks like android? Why not use the original?
Other sites are are asking the same question: http://wmpoweruser.com/windows-phone-stop-windows-phone/
If you want MS to keep metro style (which may not work) but at least tell them that you do not like the new UI design, please give your votes here: