1. That's a relative perspective. This corridor is not flat, therefore the roads will not be flat. As I said, I was talking about mostly light vehicles, and heavy vehicles downhill. 
2. The junction spacing between Fung Shing St and Jat's Incline is not bad for a more urban region. Good Hope School is only a mid-block crosswalk.  Fei Ngo Shan Rd might be seen as constrained by terrain only, and actually related to Clear Water Bay Rd. Junction spacing itself isn't decisive, as they could be coordinated, so the intersecting roads need to be compared as well. 
3. Still need to consider in context, and compare with the surroundings. It's quite different from eg Lee On Rd — Shun On Rd, and  Choi Hing Rd — Choi Ha Rd. It's not very highly localized traffic only. 
4. This only justifies NCWBR being `=primary` and more important than CWBR. It doesn't explain why the latter should be `=tertiary` rather than `=secondary` , demoting 1 more tier. 
Cf Pok Fu Lam Rd? 