They have a vision and it doesn't include 3rd party developers. I think developers were hoping for a universal message bus / directory of users and Twitter wants to be something else.
Twitter should seriously consider just shutting down their API to third party developers and restrict it entirely to their clients and widgets.
It would be a lot more intellectually honest thing to do versus just slowly and continuously stangling their developer community in their quest for revenue. If they just shut off the API then everyone would get the kick in the pants they need to move on to something new.
The Internet community desperately needs to figure out a way to build an open message bus + identity system + open API + server farm + spam killers using a foundation along the lines of Wikipedia.
Letting one for profit company control the Internet's message bus has proven to be a truly horrible idea. Going back to RSS and a totally decentralized system not good either.