The only major issue I can see is that Apple favored apps will always take first pick. If you want to say "Tweet blah blah", and use something that isn't the o

The only major issue I can see is that Apple favored apps will always take first pick. If you want to say "Tweet blah blah", and use something that isn't the official Twitter client, you're probably shit out of luck. You'd have to say the app's name or something of the sort. Another example is that Reminder will take precedence over any other third party todo app. Otherwise I think there are ways around the whole 3rd party issue with a strict approval process and having developers somehow interpret their own text commands and provide some standard feedback about what Siri's response should be.