He asks, "Putting aside for the moment the question of who is right and who is wrong, how does the Filioque enter into our preaching of the gospel? How does it affect the Church's proclamation of salvation through Jesus Christ? How does it affect our prayer and moral life?"
Here is a pithy and highly simplistic answer to that question in the form of a future thesis paper statement:
The rise of the Pentecostal movement and western Christendom's desperate (and quite often heretical) attempt to recover "Spirit led" and "Spirit filled" worship and Christian faith is, in some part, a consequence of the filioque heresy.
The Filioque, by altering western Christendom's understanding of the relationships within the Trinity, radically "depersonalized" the Holy Spirit in worship, piety, and theology.
This departure from the Orthodox Creed provided the fodder needed when Scholasticism came on the scene to reinterpret the relationship between the believer and God (as well subtly altering the understanding of synergy), and eventually produced what many Charismatics call "the lifeless and Spiritless western Christian experience."