Let me give you some perspective from the standpoint of a person who used to give pilot interviews- and that of a flight instructor too.
Even the best pilots have busted check rides. An interviewer is looking for somebody who takes the adult attitude toward that sort of thing, takes full responsibility for it, makes it right and learns from it and moves on.
Let's take a look at the situation as you've described it. You've failed MULTIPLE check rides. One failure- hey it happens, two- wow, unlucky, but the number that you're talking about would raise an eyebrow (if they even ask you at all). Failing a checkride isn't the end of the world, but pilots, being egotists, usually make doubly-sure that that sort of thing doesn't happen again- almost to a fault. It's embarassing.
Where there's smoke, there's fire, and you're describing something smoking here. You started out by laying out the facts, but then when somebody made an honest critique and opined on your situation, you got defensive. I'm seeing the red flag from something that you never even considered. Since I don't have the luxury of getting to know you for an hour or so, that's all I'll say on that subject.
Next, don't blame your failures on your instructor. It's a shared responsibility of you both. I had to laugh about the E6-B thing because although it's old-school, you should be able to use it- and weren't you an instructor already? Your instructor is supposed to get you ready to pass a check ride. That includes the oral. Any instructor should pretty much know the scenario that the examiner uses and not only prepare you based on the checkride guide, but extra emphasis for particulars that the specific examiner hits. But he's only human and not a mind reader- if he truly prepared you for every possible situation and question, your training would cost four times what it does already. YOU have to share the responsibility for learning and retaining what you've learned. If you don't feel like you can be the best applicant the examiner has ever seen, then you're not ready. Easy as that.
Back to your question. You need to give yourself some introspection. If the question ever comes up, and it was required to be asked of every applicant I interviewed, you'd better have an adult, cogent response. If you haven't really sat down and asked what are the underlying, common threads that connect all of the checkride failures and what have I done to address them, you will fail the interview. Sorry, it's the truth. Nothing is easier to detect than insincerity and you better believe what it is that you're telling the interviewer. They've seen and heard it all- don't BS them.
You wanted opinions. Here's mine. It's worth what you paid for it. IMHO, if you take my advice and get to the root of the problem, you won't fail another ride. If you handle the situation like an adult, who has learned something about himself and has made definite, positive steps to change, it will be a non-event on an interview.
Good luck.
