Buried in a long, honest article dissecting Wesabe's failure and Mint's success:
Mint focused on making the user do almost no work at all, by automatically editing and categorizing their data, reducing the number of fields in their signup form, and giving them immediate gratification as soon as they possibly could; we completely sucked at all of that. Instead, I prioritized trying to build tools that would eventually help people change their financial behavior for the better, which I believed required people to more closely work with and understand their data. My goals may have been (okay, were) noble, but in the end we didn't help the people I wanted to since the product failed. I was focused on trying to make the usability of editing data as easy and functional as it could be; Mint was focused on making it so you never had to do that at all. Their approach completely kicked our approach's ass.
(From Why Wesabe lost to Mint)
Focusing on easy-to-use features are the table stakes of user experience design. Figuring out how to meet user needs in new ways that reduce their cognitive load? That's where the magic happens...