1) Would it affect your enjoyment of the device to know that it was discontinued? I can understand if you just bought a D2 and a D2G came out, or if there was a D3G announced but the Pro is currently available.
2) No, there is no real overlap between the D2G and Pro other than a GSM radio. Very different form factors, the Pro is cheaper, the D2G has a faster processor. Both will coexist for quite some time and Verizon advertises both at the same time. Android is about choice, not one phone killing off another.