I would've thought having technical experience and the ability to get your hands dirty would be a requirement of being VP of Engineering (or similar). Two things that immediately come to mind is the ability to make competent technical decisions and estimate required time/resources required. Strong engineering/technical background is a requirement for the two. How do you even get into this leadership role without having the foundation?

I completely agree that you may not want your best engineers in this role because interfacing with and leading people is a completely separate skill, but I would still think any competent exec with a technical title will have some technical experience.