Why did the first Book of Common Prayer face criticism from both conservatives and radical reformers?

The first Book of Common Prayer, enacted in 1549 and primarily prepared by Thomas Cranmer, was designed as a compromise between traditional and new religious ideas. Because it sought to bridge these divides, it utilized diplomatically ambiguous language regarding its implied teachings, which ultimately led to criticism from both sides of the religious spectrum.1

• Conservatives: Opposed the book because it represented a departure from established Catholic liturgical traditions and doctrine.1
• Radical Reformers: Criticized the book for not going far enough in its reforms, viewing its remaining traditional elements as insufficient or inconsistent with their more extreme Protestant goals.1

This widespread dissatisfaction led to the eventual triumph of the more radical reformers, resulting in the introduction of the significantly more Protestant Second Prayer Book of Edward VI in 1552.1