2 years is way too short of a development time these days. Not to mention, at least with the last few CoD games, they can pull stuff from the previous games to use in the new releases and market it as something "new" and make you pay for something that you may already have.
Been very disappointed with the way Activision has been pulling the CoD series the last couple years. CoD4 and WaW were pretty good and I have quite a few hours logged into them. I thought MW2 was going to be fine, until I started noticing hardly any graphical changes, same basic gameplay, and the annoying server finder in multiplayer. I bought BlackOps thinking it'd be slightly better, but all I ended up buying it for was Zombies. That pretty much lead to not buy MW3 and no other CoD game until SOMETHING major changes with the whole game, not just using the same basic feel over and over again.
At least with Source, Valve is using the same basic engine, but adding new technologies with every release of it, but with the past couple CoD games, it's looked terrible and pretty much the same. I told my dad (who has bought a majority of CoD games) not to get MW3 because of how similar it was to the previous games, but he went out and bought it anyways. He basically played it for a grand total of 20 minutes on multiplayer, saw how terrible it looked and his score ended up being terrible (something like 2-15, which he normally gets somewhere in the 10-4 ratio) and went back to BF3. I don't know how CoD players can say that the game looks and plays fine, but it doesn't.
We'll wait and see what Actvision says about this "Iron Wolf" game and what it actually turn out to be. The first thing that comes to mind when I see "Iron Wolf" is the stand-up roller coaster that was removed at Six Flags Great America. Was possibly the roughest steel coaster I've ever been on, especially since you stand-up on it. My ears were in pain after getting off of that. I'm glad some other Six Flags park is getting that POS.