This is my complete breakdown of Sony wanting/not wanting to buy all of the devs, that anyone has named in this thread.
Sucker Punch- Sucker Punch is loyal to Sony, so Sony buying them would do nothing. It COULD speed up Sly 4 development, and enable the team to make better resources though.
Insomniac- Insomniac is also loyal to Sony, so again, it wouldn't do anything. They are supposed to be working with EA on their next game which is a multiplat, so I don't see them buying Insomniac any time soon. One bad thing to come out of this would be EA's partnership with Insomniac ending.
Level 5- If Sony were to buy them, White Knight Chronicles would get more installments. I could understand Sny wanting to get them because they need JRPGs, but Level 5 isn't the kind of dev they need.
Capcom- I don't want Resident Evil to be exclusive!!!
Square Enix- Like another person said, Square is heading in the wrong direction. Sony buying them would like jumping on a sinking ship.
Quantic Dream- The creator of 'Heavy Rain'already said that he doesn't want to do a sequal. Quantic Dream does more than just video games, so they would be highly unlikely.
Eat Sleep Play- I could see Sony buying them out based on wether Twisted Metal does good enough. Right now they have a thee game exclusive deal with Sony, so there won't be any buying any time soon, but I could see it in the future
Mistwalker- I doubt Mistwalker wants to be an exclusive team. Right now they are working onThe Last Story, and it is proving to be a huge project. Like I said, Sony needs JRPGs, and Mistwalker is the right team, but they want to be independent.
Monolith Soft- Monolith is owned by Nintendo right now. They could mkae some JRPGs, but I doubt Nintendo will give them up. They will be better off with Mistwalker, or buy forming their own team.
Platinum Games- MadWorld was crap, so Idon't want them developing for Sony. They will be better off with Sega