popa bar abba: I suggest that the oppositon to Rabbi Slifkin fullfills numbers 1), 5) and 6) of your dictionary entry. If the opposition was because the opponents truly believed that these were heretic thoughts, then there are plenty of rishonim and acharonim that are in the same boat.
Which brings me to Ben levi’s comments. I don’t believe for one moment that rabbi Slifkin had a “entirely novel approach to aggadata”.If you have learned a bit of Ibn Ezra all hatorah, some of the perushim of the Maharsho on gemara and many other rishonim and acharonim (Tiferet Yisroel, for example), you will see that there is a very respectable school of thought that considers aggadat just that-agggadata-and not binding in any fashion as reality. The matter of medicine, astronmomy, geology were all matters that chazal had their opinions based on what they knew in their time. And times do change. To respect your views,I will check the Pirush Hamishnayos you allude to.
Daas Yochid: the matter of kollel is one reason why I think Rabbi Slifkin had such opposition. If all one can do in life is learn in kollel, then astronomy,geology,the natural sciences, all are ‘devorim beteilim’ and should never be studied-hence,kollel is the only way of life!