Obviously a PSP2 depends heavily on what Sony intends to do in the future 
Nintendo apparently tries to battle Sony on their core market right now. Sony's problem is that they still didn't get a grip on Nintendo's expanded market so right now we have two companies, one having conquered a huge market without having to fear defeat in that segment while the other company already had enough problems in their core market because of pircay and generally low software sales.
The coming events heavily depend on how strong Sony's grip on 3rd parties is. Nintendo seems to be in a way better position right now (at least in the handheld market!) but Nintendo absolutely needs that "hardcore" 3rd party support because they can't develop games like Metal Gear Solid and Resident Evil internally, for obvious reasons and because this isn't the type of games Nintendo usually develops.
If I was Sony I'd so try to push out a PSP2 as soon as possible to defend my core market. Imagine Sony waiting another year to release a PSP2, letting Nintendo get the 3rd party support that has always been on Sony's platform! Sony's core market would be completely disrupted (literally I mean
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But I'm afraid Sony could try to release a handheld that tries to cater to the "casual" market. Maybe they've been playing a "wait and see" game and will release a PSP2 to battle the 3DS. But trying to get the expanded market without being able to keep their own core market seems like... a bad idea 
So in Sony's case I'd put out a PSP2 to defend my core business while thinking about ways to stay in the game. Everything's better than just admitting defeat. Especially because I personally think Nintendo tries to disrupt the Playstation 3's 3D gaming approach with the 3DS (feel free to disagree with me on this one, though
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) a small but stable PSP business could prove to be of great value for them. In the end they've got a lot of first party titles for their core gamers so it's not like their consoles would stop selling because of less third part support. (Though if they try to do some sort of "casual gaming" thing with the next PSP your comment would make sense).



