>These changes will significantly improve the call quality and speed of delivery of instant messages, while retaining excellent battery life of mobile devices. How does scrapping a desktop API affect mobile in this way?
Because Microsoft can update the Skype architecture so that it is more centralized like other IM applications. Right now a lot of Skype is peer-to-peer, which is not good on mobile. I, for one, am really looking forwards to this change.
[API] --> [Skype] --> [Other Skype Clients]
Rather than: [API] --> [Skype] --> [Microsoft Servers]
Changing how the network is built shouldn't affect the API in this way since there's an abstraction layer (The Skype program). It would really only affect those who have reverse engineered the Skype protocol and built their own clients.As for making Skype more centralized, yes, that will improve the experience for mobile users but it can be done without scrapping the API.
IMO, this is an excuse to scrap it and not a legitimate reason.