Well... your Wapi is a wedge and some refer to it a single concave 1/4 hollow. The point is that it is a stiff grind with little flex. Some people with heavy/tough/wirey/problem beards prefer the stiffer grinds such as wedge, 1/4 hollow.l/2 hollow, either single concave or biconcave. I am one of those guys.
I do agree that sharpness is the most important characteristic but I will not say that a 5/8 full hollow grind will shave a thick-tough-wirey beard as well as a stiffer grind. That is something that each person has to decide for themselves. Judge for yourself.
There are two things that make a big difference in my shaves
1. Beard prep
2. Patience
Just my two cents,:)