Not to make guesses at release dates, nor do I believe what game sites say and Lord Recluse has denied, but as far as how long does it take to make City of Villians, remember that the city is already "done", so it's only a matter of adding the villians, powers, minion mechanics, content and lair/mission designs. I'm not suggesting that's a small task, just that the game doesn't need to be designed from the ground up since Paragon itself already exists. I know, I'm stating the obvious, but some may not be bearing that in mind.
I'm as anxious as everyone else to see CoV, and as a casual gamer, I hope to have one hero to 50 (at 40 now) before it launches.