Flying Crane
Sr. Grandmaster
No, it isn't. It is simply recognizing that some things are designed to be done differently, and you need to learn the new thing for its own merits, as it is meant to be done. Once you understand the new thing well then you can evaluate how similar it might be to what you already knew. But as you are learning it, you are not in a position to make that judgment yet.That is still suggesting that whatever you have already learned is useless. IMO a good instructor will take whatever you have already learned, help you apply what is similar from your previous style, and empty out that which is not useless. Not tell you to ignore all that you have already learned and completely restart anew.
As an ex-kenpo guy, I can tell you that what I do now is structured and designed in a way that is fundamentally different from the Kenpo that I learned. If I had simply turned it into Kenpo, did the new method the same way as I was doing Kenpo, it would have been worthless. It is tremendously valuable, but only if done the way it is meant to be done.
Later, once my understanding had grown, I decided that for me, the new method was better, and made more sense to me. So I did switch and quit kenpo, among others, in favor of the one. But that evaluation came later.