I've been wishing for mmo's based on a couple of existing franchises the last 5 years, one of them is at least comming true.
First of, I totally agree with the Fallout as mmo concept, it's overdue, and could potentially be big sucess, but that's only if they actually sell the rights to a fallout mmo to another company.
Secondly, I've been having hopes for a conan mmo, seems some fairy godmother was listening to my late night chanting on that subject quite a few years ago.
Third, and last, on my wishlist, which I came up with just about the time Everquest left it's beta, is definetly something based of Call of Cthulhu, the horror dice and paper roleplaying game, based on H.P. Lovecraft's litterature.
On to the subject of fps mmo's, which quite a few have commented on, I'd like to point out at least one fps mmo's which seem to have been ignored.
Necron, Neocron 2. These games gave me alot of fps shooter action last time I tried them, when I wasn't francticly trying to shoot some creepy mutants in the wild with my gimpy guns, I was occupied by random players engaging me in fps action in backalleys, giving me andrenaline rushes on the same level i got when I started playing quake alot of years back. This isn't a game where you push "1" for autoshoot and wait for the enemy to die, You'll have to be able to move, aim, and think at the same time, to make it in fights here. So if you long for combat experiences comparing to those of the good old multiplayer fps games, whilest having a vast futuristic universe to play in, this is one to try. Though, I'm not playing it myself, I mostly beta all mmo's in the endless search for the perfect "drug", and I'm not saying it's the best mmo ever. But, it IS a pretty nice take of the mmo and fps mix, that's for sure.