Yeah, region changes are fine for PS2 Classics, so, it would be OK to release SIII in the PAL region. There In the US, Vib Ribbon PS1 was never released here, then got a release on PSN. Also the Cho Aniki games which were -for obvious reasons- never released here, only in japan, got released as well. The problem is emulation. If people went round changing all their games, it would be impossible to emulate properly. Even with PSN, the PS2 data has to be changed to be accomidated to the PS3, which by itself, is not powerful enough to emulate PS2 games. Hence, the early models of PS3 had a PS2 chip inside for backwards compatibility. Really, it takes hardware that is orders of magnitude more powerful that the original to emulate hardware functions inside software, and even the PS4 would have a bit of trouble emulating straight disc images of some of the later PS2 games like Gran Turismo 4 and God of War 2, which drove that system to its limit. So, all PS2 classics have to go through a process that changes some of their hardware instructions.
This is much more complicated than simple re-encoding for region, and why Sony itself decided to release games like ICO, Shadow of the Colossus, and God of War 1 and 2 as HD Collections, rather than emulate them. Same with Silent Hill 2 and 3, they were so hardware intensive, it made more sense to do an HD collection. Suikoden III, IV, and V however, are not hardware intensive games, they are closer to the Persona games and Growlanser, both of which are on PS2classics. So, I do not foresee any major problems with their emulation on PS3, and hopefully PS4. Vita cannot handle it, it is just too weak. But, the 3DS version of MGS3 and other PS2 ports went well, and Vita obviously has Persona 4 Golden and other PS2 title remakes on the way.
However, Konami does not have a good record of HD collections. . . Silent Hill was bad. Zone of the Enders was fixed eventually, about a year later. MGS3 for 3DS got delayed time and again, but was eventually quite good when it released. . . so this gets to be problematic. I still say that PS2classics with a potential Vita hard-copy release is the best bet.
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