It would be a good thing if, with this announcement, Twitter made a commitment for how this would have a support for the future.

Like "this will be available for x months/years, you can make x requests per minute/hour/day, you can buy a plan offering x for $x dollars" and so on.

Yes, that can limit some better offer in the future? Perhaps. But that make things more stable, and people would commit more to twitter.

Can you change your terms in the future? Of course. But for newer customers. The ones that sign up right now will have that promises kept. Good for everybody.