I might also point out that there is no vacuum in political power, which is what really allowed the Catholic Church to become so powerful. When the Roman Empire fell, there was no longer any government in many areas, unless it was a large enough area for a local lord to rise to power. Mostly, the Empire dissolved back into warring tribes. The only central power which remained was the Catholic Church, and so it took on many of the responsibilities formerly carried by a central government. It was also a perfect time for an ambitious clergyman to consolidate a little power on his own.

In Ferelden, there is a strong governmental system in place and no need for the Chantry to step into politics or government.