Microsoft's biggest misstep in mobile was trying to unify the desktop and mobile experience into a weird amalgamation OS that doesn't work or feel right for either. Win 10 is an improvement over 8 but still awful compared to the straightforward, non-confusing Win 7. Apple understands users expect different OSes for iPhones vs Macs.
Aesthetically, Aero is a phenomenal display of bad taste, that we'd all better forget.
When I see this kind of comment, I wonder if the commenter has actually used Windows 10 for any non-trivial amount of time.
Search anything related to Metro vs Aero or Win 7 UI vs Win 10 and it's almost all complaints about the dull, monotone, flat look of Win 10 (a failed unification with the no-longer-existing Windows Phone), or journalists who need to toe the MSFT party line in order to continue to get access to future stories.