In brief
The medieval and neoclassical environments are different parts of the common heritage.
Useful to know
Edinburgh's Old Town is connected to the medieval fortress, and the New developed from the 18th century with a neoclassical character. UNESCO evaluates their joint presence and the impact of the new urban planning. [1]
"New" is a historical name, not a promise of modern construction. On a map, compare the organization of streets and the scale of neighborhoods, then check how common silhouettes are perceived. The contrast between the two parts is more substantial than an attempt to describe everything in one style. Difference can be a source of urban integrity.
Sources
For further detail and to check the information: