One thing is noticeably clear: even the meaning of what is viewed as one of the ikkarim changes over time. Differing opinions about God’s corporeality, the character of the Messiah, the nature of authoritative texts, etc. are apparent in reading authoritative texts in our mesorah. Even when we seem to pasken on hashkafic issues, the psak is often refined and changes, often dramatically, over time. This is significantly different from how psak in halakhic matters operates traditionally.
Both our conception of God or understanding of the notion of mesorah are two relatively clear areas, at least to me. This is an area of significant difference between various traditional Jewish streams.