I believe the low total of CO kids stems from the previous staff being on the hot seat and then ultimately being fired.
By the time Bohl's staff took over, the majority of the good Colorado players were committed or had relationships with coaching staffs in place. Marty English is a prime example of a coach with relationships that work hard in Colorado.
I think next years class will have quite a jump in Colorado signees. Because the staff will have recruited and made the relationships over the summer.