If sony wants to make a successful PSP2 system I think it will need many of these things:
Flash storage as the media (optical discs aren't needed in this day and age anymore, they consume more power and load times on a portable for quick gaming sessions isn't a good thing).
2 Analog sticks and also something to make up for the lack of L2/R2 buttons (this will make ports of PS2 games easier)
Do not make a quantum leap over the PSP in terms of graphics (this helps with battery life too). Sony's being smart by having Nintendo release its system first, they'll know what kind of hardware will be in it. This is important, it will make ports for them to be easier if they have a somewhat same archeticture in their system.
Perhaps a second screen (too bad I really doubt this to happen), this opens up a lot for them such as extra button mapping on the lower screen (and hopefully multitouch). I'd expect it to be resistive touch not compactive.
Internal storage as well as expansions for SD cards (already a given due to the PSPgo having this).
Games that appeal more to the "money throwing" casual crowd that to us core gamers look like a complete waste of time (whatever to make easy money).
Put "more effort" into marketing games that are near Nintendo-area core games: Jak&Daxter, Sly, and Ratchet and Clank.
