Though I personally don't care much for SE, I still think they're an important get for Sony in terms of bringing characters/IPs back under the PS umbrella (FF, TR etc), especially now given MS owns Crash/Spyro. I'm also fairly certain Sony would want to bring whatever gci film aspirations SE has with, say, FF closer into the Sony fold, any film/game technology engines like that luminous engine they were working-on for years etc.
I'd like SEGA, but I think Sony's smart money aside from SE is in if they can buyout Capcom for a few reasons. Characters from MH, RE, DC, Capcom itself all become PS-owned, Sony can easierly navigate Marvel VS Capcom roster liscense issues as they own all the Sony/Capcom characters and have an "in" with Marvel too. If Sony also go and grab WarnerMedia's game studios (I'm mostly talking about NetherRealm Studios to be fair here), they can start playing with IPs.... MK vs SF?.... DC vs Marvel? MVC4?....