I guess it's all in the way you perceive games. I see Call of Duty as an MMO just as much as World of Warcraft since they both have addictive game-play with leveling and as you progress, you get better gear. And it all really boils down to playing games with friends.
So yeah...pretty much if a game; any game, is online, has a decently large community, and some form of matchmaking where you could play with strangers, than isn't it an MMO?
This is kind of wrong. The actual definition of an MMO is: A massively multiplayer online game. A computer game in which a large number of players can simultaneously interact in a persistent world.
The main word there is simultaneously. A game is only an MMO if a large group of players (which I take to mean more than 32 to 64 at a time as is the case of COD, Battlefield, etc...) are all playing on the same field at the same time, regardless of whether they are all in the same exact area at once. MMOs are about not only exploring the world with your friends, but being able to communicate with virtually anyone in the world no matter where you are at. Other than that I love the ideas you proposed here and like I said, that could work well in another game type, but not really fitting for a true MMO.