I'm surprised that they didn't release a version of guitar hero world tour with a usb peripheral for the psp. having gimmicky hardware is an easy way to help cut down on piracy. I mean who wants to play guitar hero just using the psp buttons? If well thought out i could see a few companies making a quite a penny without having to worry as much about piracy, and for around the price of developing a ps2 game I'd think it would be worth the risk. I would love to see iteration for RB(with mic support) and GH grace the psp. Maybe next holiday season.

I know i could be wrong because as Sony may have some long hard to comply with rules based off of creating peripherals but it's just a thought.

or because people might not buy a $70 PSP game when most are $20... (the gimmick as you call it comes at a price to customers, at least from what I saw on DS...)

Im not certain that many people would enjoy/want one for the PSP... the DS has a much bigger casual crowd then the PSP and thats why something like that became so successful.

Or they could just download one of the PC games online that turn the keyboard into the guitar in Guitar Hero. These free games also regularly get new songs to play, where as Guitar Hero players will need DLC or the next edition of the game.

You push people away from piracy with gimmicky peripherals (not saying GH is) and they get even more reason to pirate (download the game and buy a cheap second hand guitar controller on ebay).

I'm sure if a new GH edition (or any game for that matter) is good and a much bigger step up from it's predecessor then it would encourage more people to buy, I mean, the Guitar Controller gets more of an update then the games themselves do between editions.

EDIT: I should say that I don't condone piracy, but forcing people to buy excessive amounts peripherals is ridiculous (i.e I'm not buying the wii balance board, the wii sports accessory pack, mario kart steering wheel and wii zapper just to play a few games).

psp games are only 39.99 MSRP and some debut even lower i'm thinking the price would be more like MSRP, 49.99, or 54.99 since it would just be a strip with 5 or 6 buttons.

Psp can't capture a casual audience unless it starts to get more casual games. not that i don't think it hasn't any(patapon and locco rocco) but diversifying your library has never been a crime. An they need an increased 3rd party casual support.

If for the first few months of sales you don't sell the peripheral separate of the game you cut down on piracy. Once you've made money from the software (after 30 to 90) days they could get down to selling replacements. I know GH for the 360 started off with you not being able to buy the guitar separately.

While you may not be willing to buy excessive amounts of peripherals to play games i don't believe that is indicative of most, as all the things you are talking about seem to have sold pretty well regardless of the fact that some aren't even really needed(MK steering wheel, zapper)