The Great Tradition includes “the communion of the saints” of which prayer to the saints for their intercession is a necessary part. For example, St. Basil the Great (AD 329-379) wrote, “I acknowledge also the holy apostles, prophets, and martyrs; and I invoke them to supplication to God, that through them, that is, through their mediation, the merciful God may be propitious to me, and that a ransom may be made and given me for my sins.” Not that invoking the saints—St. Basil in particular—isn’t a bad idea for evangelicals in theological crisis.
Finally, the package deal includes what most evangelicals affirming the Great Tradition would probably consider the most disturbing: Mary. The Church believed “everywhere, and by all” that Mary is the new Eve, remained a virgin after Jesus’ birth, was bodily assumed into Heaven, is rightly called Mother of God (Theotokos), and intercedes for us. Christians as early as AD 300 prayed: “We fly to your patronage, O holy Theotokos; despise not our petition in our necessities, but deliver us always from all dangers, O ever-glorious and blessed Virgin.”
I could go on, but you get the idea.
Traditional evangelicals have a desperate need to set a hedge around sola scriptura in these post-modern days. And I believe the Great Tradition is precisely what they need. But, then again, I’m a Catholic.