As far as acquisitions I think Sony should make in the future:
Quantic Dream: I'm not sure how well Beyond Two Souls did (I haven't bought it yet, but it's on my list, as I loved Indigo Prophey and Heavy Rain), but they seem to enjoy working with Sony, and David Cage has expressed interest in being purchased by them one day, despite liking the current arrangement.
Drinkbox: I hate to deprive other gamers of Drinkbox, but they've done a fantastic job on Sony platforms with the Mutant Blobs and Guacamelee series, and I don't think it'd hurt them to be picked up by such a big company. They do really well, so I doubt they're looking to be picked up, however.
Housemarque: Same as Drinkbox, but their PlayStation offerings have been damn amazing. Stardust, Dead Nation, Resogun, Outlast, these guys have skill, and they'd only be an asset to Sony's digital arsenal.
Sanzaru: I know they're doing Sonic, but they did a fantastic job with Sly: Thieves in Time, and I think it'd be great if they took over the franchise for good while Sucker Punch works on inFAMOUS and new IPs, and maybe they'll grow to the point where they can produce their own original IP in the future, with the backing of Sony.
Ready @ Dawn: Super talented developer who has killed it on the PSP with the God of War games, and the order looks sick as fuck as well, but I think, if the Order does well, an offer may be thrown out there. I have no idea if RaD is interested in being bought, however.
Bluepoint: They do such a fantastic job with porting titles to the PS3 and Vita, I'd like to see them be brought on as an official "port house" for PlayStation; handling whatever HD classics Sony is planning in the future. Then, when possible, they can start to produce their own content on various platforms (mainly Vita, dammit!).
Ninja Theory: Bam, dark horse entry! I personally am a big fan of Ninja Theory (Heavenly Sword was fucking awesome, I don't care what people say!), and think they have some great ideas and concepts, but lack that extra bit of support/polish I think they'd get when under the umbrella of a big company. I think Heavenly Sword is still their best game on a tech/gameplay level, and I feel a lot of that was because they were creating an exclusive title for Sony, and no doubt got a lot of support. I imagine they'd do extremely well under Sony, with studios like SSM or GG offering tech support/resources. Honestly, I just want Heavenly Sword 2. So sue me.
I think Sony snagging one or more of these developers would be a boon to the company. They're all fantastic at what they do, and they've all worked with Sony in the past, and seem to have a great relationship with the company. Sony's current First Party is populated with some of the best developers in the industry as is, so acquisitions of the above would be great.
EDIT: Back in the day, I wanted Sony to buy Level 5. Maybe it was around the time Rogue Galaxy released, but I thought Sony needed an RPG house, and Level 5 had mainly just done PS2 titles at the time (Dark Cloud 1 & 2, DQVIII, and Rogue Galaxy). They weren't as big as they are now, so I figured it was a no brainer for Sony to snag them. They didn't, sadly, and now I think it's way too late.