Impending server merge is both obvious and needed; they're not going to split them up by region though. Part of what makes XI efficient is that essentially two player bases can live on the same server, and outside of a little overlap, basically play on different schedules. That means the same server supports far more players than it would if everyone was playing at the same time. So 16->8 (or maybe even 4!) is likely, but they'll continue to be integrated.
F2P is unlikely. SE values the Final Fantasy name a lot. Look at the lengths they went to in order to save XIV, rather than just write it off, because it was a numbered Final Fantasy. That matters to them, and they're not going to tarnish the brand. Cash shop is pretty likely, though.
Mini-expansion(s) along the lines of the Add-on scenarios is probably pretty likely; Something more full blown like Abyssea would be nice, but I think at minimum we get something with some lore to it, since Adoulin is essentially wrapped up.
PS2 is dead. 360 likely as well, with some kind of program to get keys for the PC versions if you have existing PS2/XB360 keys.