I doubt Sony are gonna buy Ubisoft or Take Two. They would be too expensive and I don't think depriving other gamers from third party content is a good idea.
Like I previously stated Sony need to expand their own studios especially Naughty Dog, Media Molecule, Santa Monica etc. Some of these studios should be two teams. They should also form a Polyphony Digital European studio to maybe expand GT development.
As for buying they should get
BluePoint but expand the studio
Kojima
Housemarque
Sumo Digital
Remedy
For a big purchase Kadokawa including From Software. That would tie in with their Anime plans.