No it would be a mistake. First, that new OS is at least a year away. Can you afford to leave vulnerable servers in production for another year? Second, you are talking a 13-14 year gap in technologies, which would guarantee incompatibilities with old apps. For every generation of Server you get away from 2003, the migration becomes that much harder. It's best to start now and get the process going. Server 2012 has almost a decade of life left in it.