Glittering Wish seems awfully slow. I mean, Tarmogoyf often looks slow in this deck. But then, people do play Zenith, which is even slower (compared to Goyf, not to Wish). I guess if you are a very midrangy Zoo, you could try it. But in my opinion Zoo is neither supposed to be a midrange deck nor a silverbullet answer deck. The targets don't even look that enticing.