That seems like a bit of a straw man: the official OS X native version of vim, MacVim has literally all of those key map pings by default – cmd+c to copy, cmd+a to select all, etc.
Now, the OS X Terminal (and programs run through it, including vim) does support Cmd-C (after highlighting with the mouse), Cmd-V, and Cmd-A, because the OS can treat them as raw text without the terminal knowing anything about them. It doesn't support Cmd-X, Cmd-Z, or even basic navigation keys like Home and End.