Not sure if information is available yet about how DLC will work for BOII, or how it will integrate with Elite.
I don't think you can draw any conclusions about how best to proceed without seeing this info.
I would also take into account where you live, or perhaps more acurately how many people are online when you play. When I play, Elite playlists are useless, as there are consistantly less than 2000 people playing in them, and getting a match is almost impossible.
I have come to the conclusion that if Elite and DLC are organised the same in BOII as in MW3, I won't be getting Elite again, because it doesnt work for me.
With 20/20 hindsight, and the way BO worked, I definately would have prepayed for BO DLC. But you just don't know how good the DLC will be. BO DLC are some of my favourite MP maps, Zoo and so on. But liking the maps is not gauranteed.