I would think that Windows 10 will either be the saving grace or the final nail in the coffin for Windows Phone. If Universal Apps take off, there wont be any excuse not to develop for Windows anymore. 1 billion prospective users is something you don’t simply shrug off and not care about. It’ll be a rude awakening for app developers. This is dependent on Win10’s pricing models and everything though, if its poorly executed then there’s not much of a point.
On the other hand, because Microsoft is unfortunately the tech company everyone loves to hate, if Universal Apps cannot command attention and respect from developers because its not good enough, then WP is all but done for.
The point about MS apps being better on other platforms is unfortunately a very valid and real point. What I think MS should do is to have a few “whips” inside the company, that can assist other departments with Windows platform development (yes Skype we’re talking about you). These “whips” can also have their services offered to other 2nd party app developers, as some form of Platform Ambassador or something.
And another thing. The US should be deprioritized when it comes to web services. It seems almost a lost cause there so I don’t think MS should waste too much resources there. As WP is going very strong in Europe comparatively, the priority should be for MS web services to be better in their power bases, like Europe. Just my own two cents.