Yeah. Have to agree with you here. I just tested this recently , getting a few hundred retweets of an obscure URL ranking on page 4 for an obscure term and it moved to page 2 within a few days. I suspect Google may not be getting Twitter data directly (or getting it as fast as when they had the direct relationship), but, at the very least, there's a strong second-order impact between pages earning lots of tweets and getting ranked.
Is that 'second order impact' not tied to the public doing the link building for you, outside of twitter? E.g. blogs, reddit, etc, rather than Google actually putting ranking weight onto info in tweets?
Our latest public post on this is here: http://www.seomoz.org/blog/do-tweets-still-effect-rankings but we'll continue to test and try to get more definitive answers.