Yes Drawing is most important thing not only for Diploma, But also it is important for all. But is much more important for Diploma as it will have more Diagrams.

Architecture is not about only drawing,but it is about creativity and the ability to communicate and express  your ideas. Architects do use hand- drawings and sketches to communicate their design ideas, but also use computers softwares for designing purpose

hey,

to pursue diploma in architecture you must have these skills in you , candidate must having their area of interest in the domain of building design and construction and candidate must have a creative , analytical and technical mindset and yes of course you must have good hand on free hand drawing

all the best!