The pulpit rabbi of my last shul told me that when Boteach’s book “kosher saxophone” came out, he felt that he has to read/skim it, as people might have started asking him questions about it. He said that, as far as he could tell, there was no kefira nor anything against halacha in it. Maybe writing such a book is a problem, but the contents were not incorrect.
Anyway, it seems to me that Boteach is not OTD with halacha, nor with most of his hashkafa. It seems to me that trying to mekarev the world can be… well…let’s just say unusual and potentially problematic.