imo, they should target Capcom if they can. They have more IP worth compared to Konami at least. Square-Enix would be too big and expensive.
Why are people even suggesting that Sony should buy those companies? They just spent over $1 bil buying Ericsson's share out of their JV.
SE Market Cap is Y174.8B. Buying up the remainder of Square Enix would command a premium on their shares and cost more than double what they paid for Ericsson's, buying a majority share on that company would probably cost $1 bil. A very risky, unattractive buy for a company with a declining WW IP (FF) and really just one major, system selling IP in one region (DQ). They do not own the Kingdom Hearts IP. They own a rich amount of IPs that were system sellers at one point but are not right now such as Chrono, Tomb Raiders, Xenogears, etc
Capcom's market cap is Y110.5B. Buying up Capcom is also a costly and risky proposition that would cost more than buying Ericsson's shares. They have one major, system selling IP in one region (MH) and one major system selling IP WW (RE) and one major, but not really system selling IP WW* (SF). Good game series like Megaman, MvC, etc are not really system sellers.
Konami's market cap is Y279B. Needless to say, this is completely out of the question and not a smart buy at all. They have one major IP WW (MGS), one major, maybe still system selling IP in one region (PES/WE). Good game series like SH, Castlevania, etc are not really system sellers.
Really, I think these suggestions are ludicrous. If one would like to see Sony and Kaz turn around SCEJ, it would have to be through A) Building their own internal team and hiring talented people to work for them, and/or B) Buy up smaller, yet worthy developers. Gust was up for sale and would have been a good purchase, but Tecmo-Koei bought them up for Y2.2B. SCEJ probably never considered it but it would have been a good purchase. From Software and Game Arts are two that comes to mind. They are probably at the right price if someone is interested in snatching them up and they are both worthy developers that hold worthy IPs. Platinum games is another worthy purchase even if they don't own any real noteworthy IPs. Even Mistwalker would be good with Gooch there. L5 is probably too expensive and a risky investment like the 3 above.