I doubt it is cross game chat... Sony have proven that after 3 years they haven't put it, more than half of the PlayStation fans ask for it and still nothing. So I guess Sony for some reason don't want/can't implement that feature.
I mean you know every company have to please their customers, so 3 years, and more like half of the users asking for it, that's simple enough reason to put it. But again there might something....
they might finally put in cross game chat just to please current customers for the inconvenience of not having PSN for 2 weeks and also to attract more customers cuz they would to do a lot just get out the hole that they dug themselves into