With everything that I write, there are always people expressing their comments and their beliefs as to how true/unacceptable it is. I was therefore amazed that I didn't get a single piece of feedback on my article in Hakirah “They Could Say It, We Cannot”: Defining the Charge of Heresy. It dealt with an incredibly important and provocative topic that lies at the heart of the Torah-science controversies of the last few years: the very definition of heresy. It's now freely available for download; click here. Since writing the article, I have been working further on the tricky topic of defining heresy; I gave a lecture on this topic recently in LA and I plan to write a full treatment of it. Meanwhile, here's a fascinating quote from Prof. Haym Soloveitchik. He raises the question of why Rambam listed belief in the preeminence of Moshe's prophecy as a fundamental; would anyone really care if someone believed that, say, Yechezkel was his equal? He answers as follows:

...An ikkar does not arise from the fact that its negation is false, but from the fact that its negation undermines the Jewish system of belief. That Moses’ prophecy was of a different order than that of other prophets is an explicit verse in the Torah (Numbers 12:7); [but] it was a specific historic context, its denial by Islam, that turned this verse from a religious dictum into an ikkar. A belief is an ikkar when its content is what differentiates Judaism from the surrounding credal system.
(“Two Notes on the Commentary on the Torah of R. Yehudah he-Hasid,” p. 244)