Mistakes were made with the PSP, says Sony, but they won't be repeated for the Vita.
Shuhei Yoshida, head of SCE's Worldwide Studios, says that there was a lot more than Sony could have done with the PSP. He thinks that while the PS2 quality visuals impressed people at first, once the novelty wore off, there wasn't a lot else there.
He said that the PSP didn't really offer a unique experience, and that with its smaller screen and single analogue stick, it felt like a compromised version of Sony's home consoles. Yoshida said that this wasn't a mistake that Sony was particularly eager to repeat with the PS Vita, and that Sony had spent a lot of time making sure that it was offering something that people weren't getting anywhere else. He added that the studios he oversaw, which includes the likes of Naughty Dog, Molecule Media, and Digital Polyphony, had spent a lot of time making game prototypes for the Vita to ensure that the games were doing something special.
The Vita is certainly packed with more features than the PSP: as well as having a second analogue stick, it has a touch screen in the front, a touch pad on the back, and as a gyroscope that enables motion controls. Of course, it's not just hardware that makes a platform successful - the best hardware in the world won't help you if your games suck - but with so many options available, developers will almost certainly be able to come up with something fresh and interesting.