There is no such thing as a stationary tradition. Traditions are always developing, living things.
Oliver D. Crisp[John] Calvin is revered as a thinker of immense importance in Reformed thought, Jonathan Edwards could say in his preface to his treatise on Freedom of the Will that he had derived none of his views from the work of Calvin, though he was willing to be called a "Calvinist" for the sake of convention.
Oliver D. CrispThe alternative of hypothetical universalism, according to which Christ's work is sufficient for all but efficient only for the elect, was alive and well in early Reformed thought. Moreover - and importantly for our purposes - this view was not regarded as an aberration but as a legitimate position that could be taken within the confessional bounds of Reformed thought. But that means that the Five Points aren't the non-negotiable conceptual core of Calvinism after all.
Oliver D. CrispThere are constraints on what counts as "Reformed." It's more than a name or a label. It's about belonging to a particular theological stream or tradition, which is shaped in important respects by particular thinkers and their work, particular arguments and ideas, a particular community (especially, particular church communities, denominations, and so on), particular liturgies or ways of worshipping and living out the Christian life, and particular confessions that inform the practices of these communities.
Oliver D. CrispFor those interested in Reformed thought more broadly, I'd recommend Peter Leithart's recent book on Reformed Catholicism entitled, The End of Protestantism: Pursuing Unity in a Fragmented Church (Brazos Press, 2016), as a thought-provoking and stimulating read that should get us all thinking about the future shape of the Church, wherever we come from.
Oliver D. Crisp