I work a bit with game commision officers in my area (have a hunting store) and I havent heard anything lately about it. I got a trapper ID which was a painless, fax the form and 3-4 days later I had it in the mail. Its permanent and easy to acquire, kind of a no brainer. Problem I see with CID is people could use fake or someone elses numbers and be unidentifiable.
Although using the CID sounds like a logical thing to do, I believe they will continue to use separate ID #'s because of confidentiality issues. The trapper ID # is a confidential number and there are laws governing what information may be disclosed about the registrant and who that information may be disclosed to. There are a different set of rules governing the CID #.
Cid can be entered into any license machine and a birthdate and info is there. Theres just more hands throughout the state that work with CID. Only ones who know and cant access trapper ID info is you and game commission personel.