I think the institution I'd want to go to,and the one that creates the most educational value overall, would be one that tries to find a good balance between the two types (and while there won't be many ideal types and most people will be on a spectrum blah blah! I think most people in the ability range were talking about will veer clearly towards one or the other).
I do not think that an institution who tries to limit type b to only 10 percent of candidates will create as much overall educational value as one that moves the percentage closer to 50. Having pointy types dominate might not be good for either type of student.