What really needs to happen is an open decentralized protocol needs to be agreed upon for newsfeeds + blog posts (wordpress) + microblog (twitter). Then everyone can write their own servers and clients and operate in a manner like Email currently works.
Then do it. Make everyone look like idiots for not doing it sooner. Make it so cool I have to sign up.
As a developer, I never thought once about building an app or integration for Diaspora.
That's why App.Net might have a chance -- he's making this about targeting developers. There's a reason Apple has spent millions marketing different 3rd party apps -- and the whole ecosystem via "there's an app for that". There's a reason "killer app" is part of our lexicon. There's a reason Steve Ballmer jumped around on stage screaming 'Developers!' and there's a reason XCode is free now.
Building it is not a guarantee that they will come. But it is a prerequisite.