Some very excellent suggestions and points made here. it helps me clear my head and focus on what is most important. I will move on and let it go. I'm am amazed and frustrated with myself for continuing to be so angry with this man. But admittedly, I am more frustrated with myself for putting up with it for four years.
I'm sure you've already done this, but it may be worth doing one last reality check. Given that comparing your progress to that of other people is always dicey, are the others who have also trained four years (and who train at the same frequency as you -- that's important) being advanced when you are not? Are they being given access to teaching that you are not?
If there's a discrepancy and it's time to move on, I think you can tactfully explain your reasons why, both to your current sensei and to your new sensei, who may well ask why you left. "I'm training regularly, but I don't seem to be making any progress" would sum it up pretty well, no? That takes ownership rather than blaming, but at the same time makes the point that you are trying and it isn't working for you at this particular dojo.