1. Sensationalism aside, Dropbox should review questionable security claims to reduce false sense of security if any. With millions of users, careless words formed out of marketing needs are no longer needed. What Dropbox users need now is more clear picture of what they are giving up to gain Dropbox's services.
2. The weakest security link is the user and their computer, not Dropbox which has enough financial incentives at stake to be diligent security wise. In the end, no computer open to external data or code is safe. What protect most users today is actually not security technologies but cost/benefit ratio to potential attackers, tempered by goal and scale. 99.9999% of Dropbox user data is useless to attackers and cost of mining questionable nuggets out continually expanding sea of data from 20 million users is not a trivial task.
3. While it's true that user must trust Dropbox in the end, some of its security measures could use strengthening even if it's just intended to raise the level of sophistication necessary to steal Dropbox data.