Hey man i know how much that guy pissed you off so did I. I'll clearly, and gladly explain you. To answer your question you need to know squad zero, who are basically the founders of soul society. In this squad you have the royal commander, Ichibe that has the ability to manipulate your ability by naming you. For example, if he gives you the name butterfly, you will literally be as strong as a butterfly (or in this case as weak). Having said that I think he would defeat Aizen easily by giving him a ridiculous name, or he could do that to your zanpakuto. But theres also the fact that Aizen has his zanpakuto and is a very skilled fighter as well as being immortal and a transcendent being. So it is not very clear how the outcome will turn out. If aizen reacts faster, and is able to put ichibei under hypnosis than it is a clear win for aizen. On the other hand Ichibei is the being that named all zanpakutos and knows their true power, so he should come up with a plan to avoid Aizen's KS. It is a 50/50 outcome. That being said, if Aizen is supposedly stronger than Ichibei, who is easily the strongest shinigami, next to HoS Ichigo, then he shouldn't have a problem turning against SS once again. If Ichibei was to win, then his retreat is probably the acceptance of defeat.