Some people view passion as an important part of motivation in a job - as in a passion for robotics meaning a programmer spends more time and energy in solutions for a particular team that makes robots than they would otherwise in any other position.

Clearly, given your process, you won't be hiring people who are passionate about certain areas, though they will be happy to work on anything, so the hiring process suits you and finds you generalists who are happy to work on any project (exactly what you want), but it will put off some potential employees.