I've also been thinking about this recently, it would be a win win 
Us: The game could detect whether or not you own black ops. If so, it will unlock the re-mastered versions of Kino and Five.
Each Black Ops map pack you own could unlock the re-mastered versions of their respective zombies maps, including rezzurection to unlock the World at War maps.
We would then get the maps we have already payed for again with new features such as host migration and improved leader boards for free 
Activision: For people who have Black Ops 2 as their first game, they will fall in love with zombies like we did in World at War, and instantly buy the Black Ops map packs in order to unlock the previous zombie maps. After discovering they have purchased 12 multiplayer maps for Black Ops, they may buy that too. (Only the zombie maps should carry on to the next game for these business reasons, and to keep Black Ops 2 fresh and interesting)
Sales of Black Ops will increase, Sales of Black Ops Map packs will Increase, Reputation to fans will improve by offering a free upgrade to their already paid for zombie maps for loyal returning customers.
The downside is the player count on Black Ops zombies will fall, but they already have our money, so hey, just keep up with the times! 
The way I see it Activision will not miss out financially by doing this, but will gain a much improved reputation. It seems they are already trying to reward loyal customers, such as with MW3's free prestige tokens for each previous COD game you prestiged in, so I guess this is not completely out of the question. The thing is, would Treyarch waste their time remaking 10 maps that we have already paid for just to be put in a new game? I'd imagine they're rather busy with new maps to be honest... 10 maps are a lot, so I'm guessing they will start fresh with Black Ops 2, and just tell people to play old zombie maps on old COD games, which is understandable. But we can always hope... Let's just hope they don't recharge us for the same maps again like with Black Ops and Modern Warfare 2!
Maybe if we raise awareness, we can get Treyach and Activision to do this, even if the old maps are released after the game?! I'm sure there will be high demand for this if people find out it's possible...