As far as the PSP's flash memory goes... well there is a theoretical liit on how much stuff you can cram into it's Random Acess Memory, but that amount changes all the time with disoveries of new programming techniques and it dpends on how you compress the files and what acess system you have so they probble could have fit those specials in there but it also would have meant a longer time to program the game (as each needs their own graphical animation aswell as data on how that affects the character, not to mentaion bug testing and balanccing of game mechanics) so it would have had to come out later, which din't fit with the companies schedule and would have cost them much more money. While it's probably true that with the system they used they were reaching the limit of the PSP's memory, it is also probably true that they could have iplemented the specials you suggested if they had really wanted to.