it may be a bit late for this idea but here is a suggestion i made for the merging of the crysis 2 DLC
that could certainly be adopted and work in crysis 3. http://secure.gamesas.com/forums/viewtopic.php?f=42&t=47460&p=498284#p498284
if this idea or something similar was introduced it would be half the problem solved.
having normal maps in rotation with the DLC maps in a separate lobby would not divide the community as much.

the high price of the DLC is a concern, i don't know if the price is set by EA or crytek marketing team but they really need to be more informed about the community size.
even if it was 8-10euro you would get double the sales, providing integration is done right.

crysis 3 support is leaps and bounds above crysis 2 support, don't fall at the last hurdle.
please don't leave us hanging crytek communication is key