The DC and the SAN are two different tracks. We look at our certifications in terms of industry relevant job roles, and as long as the job roles are relevant, we maintain the certifications. The number of poeple seeking a specific cert also tells us about the market impact of it. So, to answer your question, the fact the the CCIE DC is coming, is not impacting our decisions on the CCIE SAN. Any change to any of our major certs are announced with at least 6 months notice.
If you are a Data Center person, pursuing the CCIE DC will definitively give you edge, but if you are not, you can stick with the SAN. Thanks!