Up until this game came out I always thought the latest CoD out at the time was better than the last. I thought MW2 was better than WaW, partly because WaW was such a cookie cutter copy of COD4, nothing really new added. Then BO came out and it made me realize just how gimmicky and cheesy MW2 was, and I felt it was far superior to MW2. Then this game comes out and while it's an improvement over MW2 it's not nearly as good as BO in my opinion.
Some of the things they claimed to want to try to do in this game were better accomplished by BO, such as trying to make the game more gun on gun oriented. And despite them claiming to want to reduce camping they created many of the maps with very tight spaces and 'cover' objects cluttering up the maps which only provide campers with additional corners to camp in. I also think that as a whole the maps in BO were designed better in general. At this point I just view both developers as putting out entirely different games almost. So is this an improvement for the MW line of games? Yes. Do I think Treyarchs line is superior at this point, sure do.
Don't get me wrong this game is fun and all, but I'll be eagerly awaiting Treyarchs next installment. And trust me back before Black Ops came out I would have never ever believed for one second that I'd be sitting here right now saying Treyarch is putting out the superior CoD titles, I'm not just a fanboy.