Oy, please no!The best thing Apple can do in terms of GUI user-friendliness is to do a 100% purge of every last pixel of flat design and all flat design variants like neumorphism and glassmorphism, and then work with Scott Forstall in some capacity (even if limited) to bring back all of iOS 6's exact same skeuomorphism and Mac OS X Mountain Lion's exact same skeuomorphism. Forstall could help to update their resolutions for the higher-resolution displays of today, as well as to create new skeuomorphic graphics and icons for things that exist now that didn't exist when those two operating systems were originally released.
I don't hate skeuomorphism, but it got completely out of hand but the time iOS 6 and OS X Mavericks rolled around. I look back on screenshots from that era, and everything looks almost amateurish and toy-like.
That's not to say Apple couldn't add some skeuomorphism back into their designs, but Forstall is definitely not the person to help with that.