Why do we seem to know more what exactly constitutes Apikorsos than earlier generations knew?
Areas of Hashkafah that were in dispute in the time of the Rishonim (Rambam era) have been decided by some with certainty.
As I understand,even full prophecy can not resolve a Halachic uncertainty.
Whatever Ruach Hakodesh is, it can never be put on the same level as Nevuah (prophecy).