The PSP 3000 model introduced some new improvements to the existing Slim & Lite (PSP 2000) model, but it took a major step back in the LCD screen department. Reports of ghosting, interlacing and unnatural color reproduction have made the new PSP an unworthy upgrade of the previous Slim & Lite. The screen is very important, since we do spent many hours staring at it. So, here's a wish list for the inevitable future PSP 4000.
Include OLED (Organic LED) screen technology. It puts LCD and Plasma to shame with superior color reproduction, amazing contrast ratios, no dead pixels, no response rate issues and no backlight needed. The OLED screen creates its own light and is reported to be visible even in sunlight. It also uses a lot less power which is a must for handhelds. It's time the PSP makes use of this excellent new technology.
Bluetooth would also be useful for various reasons such as sharing content with a cell phone or connecting to the internet if not within wireless reach.
And of course trophies. Why are there no trophies in PSP games now that the PSP is able to access the PlayStation Network? This should have been included in an update a long time ago.
The final missing piece to the puzzle is AAA games. There's just not enough AAA titles on the PSP, with lackluster support from Sony having put the PSP in its current predicament. Gran Turismo Mobile that was shown before the PSP even launched and still hasn't been released. It's no surprise PSP owners are dissapointed.