I have a Windows Phone and I also have something like a total of 50 Universal apps, of those for will run in the phone. The idea of having one setup on multiple devices is laughable. If they don't fix that it will never take off.
Considering my bank apps, my work apps and a majority of my most used favorites plus cool tech like NFC payment and VR isn't on WP, i can't switch full time. I use my Note 5 for many things which cannot be dine in MS's cute little world. I do have a WP, 640xl, used for testing, but MS needs to catch up with last year's tech first. They are still 5 years behind in tech.
They are going to target Businesses - Continuum and the new Remote Desktop UWA will allow businesses to deploy Windows 10 Mobile Devices to field staff using Azure Remote App and Docks to give PC experiences.
And if the Surface Phone uses an ATOM X3 or X5 it will be able to natively run x86 applications.
If the 950 xl would've been just a little bigger and with a stylus I would've been sold. They improved screen resolution and internals. I use Office and One Note often with One Drive. Having the stylus would've been great for me. The other problem is apps. Windows store just needs more apps. I love my Sp3 though.
I got a Windows phone yesterday. I just love how it feels compared to Android, which feels like a toy. But honestly I am not their target, I am in business but all I care about is the camera quality and camera software. I got the Lumia 1020 because of the 41mb sensor and Image stabilization.