The most important factor in my decision to buy any consoles is the games it has available. My main gripe with most PSP games is I would usually prefer to play them on a TV with a proper controller. One of the things they demonstrated at the PSP2's unveiling was a couple of full blown PS3 games that had been successfully ported to run on the PSP2. Naturally, my first thought was that we were in line for even more big console games played on a tiny screen. However, what if those games could be equally playable on both the PS3 and PSP2? Sony claimed they still intended to support digital downloads as a means for distribution alongside traditional retail releases. If Sony has the foresight to let us download and play games released for PSP2 on the PS3, not only would PS3 owners get access to more new games, but developers could push forward with them knowing that the install base for the PSP2 is incidental to the potential gamers that might buy what they're sellin.
Looking backward, I see another interesting opportunity for the blending of the two platforms; PSN downloadable games. If a PSP2 can run MGS4, it would stand to reason that it would also run Joe Danger or Lara Croft and the Guardian of Light. Much like running PSP2 games on a PS3 would increase the potential user base for PSP2 development, the ability to run PSN downloadables would increase the number of possible customers for all those 10 and 15 dollar titles, as well. Imagine being able to take Pac Man CE DX with you, anywhere you go, anytime you want.
The icing on the cake for me would be full trophy support and cloud saving or at least the ability to sync saves between the two platforms. That puts the power of choice in the hands of the gamer and makes it more a matter of personal preference. Even though I do not really have any interest in this thing based on the price, the idea that I might be able to play a game on a home console and move it to a handheld to keep going is pretty damn exciting to me. Time will tell if any of this is even in Sony's plans for PSP2, but thinking about it sure is interesting.