2) Don't like App.net? Pick Reddit vs Digg, same case. One managed to "get by" with a core team, the other took a ton of money, hired a bunch of folks, made a bunch of promises, and tried to shoehorn their original vision, the one that got them established in the first place, into something completely different. Reddit, makes money and is sustainable -- it just didn't need to make that much money -- as a user that's fine by me, and the reason why Reddit "won". If only Digg was happy to "just" be a $50mill website...
3) Twitter is what it's users/supporters made it to be. Its service/value was understood from the get-go, and in turn, it's popularity grew for that same reason -- ppl understood it's vision and supported by building upon it -- hence cannibalizing your core base by knee-capping your API, probably isn't the best way to go.
4) My vision of Twitter is fine, like many others, I think it's got something to do with SMS-web-mobile-140-characters-distributed-micro-messaging-or-summin? Does it need to be more than that?