I'll still be interested in playing Firefall when they get some of the content I want implemented in there, provided a group of us here are playing when that time comes. Otherwise I probably won't touch it much.
As for the others; I took some time away from GW2 to play Dishonored, AC3 etc when they released last year and have been back in once or twice since but kinda lost interested in it if I'm honest. Just haven't had a desire to play. Maybe I will again one day - good thing with F2P games hehe.
MWO - Never had an interest for mech stuff personally.
PS2 - Kept meaning to give this another try but haven't gotten around to it yet. I'd still like to but I don't know when that'll be.
I know you specifically mentioned MMOs and I don't know how long this will last of course, but we currently have a region in SimCity atm which 9 of us are playing in. There's still quite a few problems with the game but it's great when it's working, you're more than welcome to come join us if you're into games like that Oz
Future MMOs? There is only one I have any particular interest for atm and that is World of Darkness, which they'll be showing a bit of next month at the EVE fanfest so I read. I will be following that one very closely when they start churning more details out. Oh and probably project Titan from Blizz given how much I used to enjoy WoW, whatever that turns out to be.
Don't know of any others of the top of my head, none which have caught my attention at least