Well, as far as Call of Duty goes, I prefer Treyarch's games nowadays by far and wide. Modern Warfare 2 and 3 were terrible messes, in my opinion. Black Ops, however, I enjoyed more than any COD game since COD4, for two reasons: First, the STORY. Oh god, it's the first time they have gotten that aspect right in a Call of Duty game. The problem with shooters that try to present a "realistic" scenario is that they usually detach the player from the action on the screen both by making the story an extremely dull "carry out the mission" scenario, or by switching back and forth between unrelated characters.
In Black Ops, the story was rather fascinating and unfolded like an actual story, with actual compelling characters and plot beyond "serve your country!" I loved it when they
that was one of the best "a-ha!" moments in the whole game, even though they blatantly hinted at it several times. It wasn't done perfectly, as you still had the sections where you didn't play as Alex Mason, and it wasn't a masterpiece by any means, but it was a huge stride forward for the series.
Then the multiplayer. Oh god, they actually went out of their way to make the online multiplayer much more compelling by adding the original Wager Match modes, which are by far the most fun I've ever had playing COD period. Not only that, but the sheer wealth of modes made online play extremely compelling.
Modern Warfare 3 sucked so much because it seemed like they took all the terribly bad things about Modern Warfare 2, made them worse and then ignored all of the big improvements Treyarch made with Black Ops. It's so strange how Infinity Ward has dissolved and continues as a husk of its former self making these average games, and Treyarch, who started making the side-games, is now making the better games in the series.
Anyhow, I have big hopes for Black Ops II, and I'm hoping it makes it to the Wii U. The branching story and famous author makes it sound like they are continuing the improvements to the campaign, and this finally adds replayability! I've never been compelled to play a COD campaign more than once, but this might just do it! Also, I'm loving this near-future setting they chose. Now, all they have to do is get the online balancing right for once.
As for the story itself, I hope they do a good job explaining why Woods is alive when he died right in front of you in Black Ops. It might be because by that time in the story Mason was already cuckoo and it was just an illusion or something, but I just hope they don't outright ignore it or pull an "it was all a dream" for all of Black Ops's story.