The phrase "wonderful richness" means something that is incredibly special and valuable. It suggests that there is something truly remarkable and abundant in whatever is being described. Full definition
Scripture and the Fathers, always quoted from memory, would be drawn in, creating a wonderful richness. (faith.org.uk)
The very fact that it is we who are speaking has its own added significance, for it indicates something of the wonderful richness of the gospel by which the Church lives. (religion-online.org)
the brown butter lends a wonderful richness + nuttiness, while the sea salt cuts through the sweetness with a surprisingly awesome kick. (fearlesshomemaker.com)