There are enough things to improve with W10M where you don't need to use an iPhone to find them out.
And this since quite some time. He should have done that work while he was in charge of this.
And instead of copying what he will find out whith using an iPhone, why not use W10M deeply, finding the bugs and thinking what would be really cool to have INDEPENDENTLY from iOS or whatever. He won't find out what a traveller misses with W10 when he is using an iPhone.
And if he thinks a cool app is missing...there are teams at MS who don't know what to do with their time, so they started to bring selfie and keyboard apps to iOS.
Let them program the app Belfiore could possibly miss.
With such leaders, MS will get nowhere. Well, he was leader wit WP7, WP8, WP8.1, and until the start of W10.....his track record isn't really one filled with leadership, with pulling strongly, with being fast and effective...
He'd better go to market something, instead of being responsible for a product line.