Okay, why does Sony not understand one of the main issues this system has: no second analog stick. It isn't held back by size. Never really was to begin with (except for the overcomplexity of the UMD drawer, it breaks too easily when dropped in the 1000 model). It isn't held back by a bad screen (of the handhelds, the PSP has both the largest and brightest). It isn't held back by bad graphics (any game that has bad graphics is the damn developers fault, look at CC, GoW:CoC, R&C:SM, etc). It isn't held back by it's clockspeed or cpu (its definitely the fastest of any handheld, except maybe the iphone). It isn't held back by lack of features (internet, phone service, audio and video codecs, and loads of features accessible through hacking such as an ISO loader, a high quality ps1 emu, emulators for nearly every retro console, an ebook reader, and the list goes on. The DS has absolutely nothing except for games, and a few decent emulators accessible by hacking. The iphone is the only competitor for features). It isn't held back by price.
HOWEVER, it is held back by camera issues for games like Monster Hunter (tolerable, but could be much better), and the great difficulty of creating a quality FPS due to control issues (rarely tolerable).
Instead of releasing all of these models with decreased size and a better screen, they should just add the damned analog stick!!