People are different, with different mind, and intelligences. Forcing such a designer to "code" is just going to destroy his skillset, that otherwise would be of great use in a good and collaborative team. :)

Having worked with designers ranging in skills from pure photoshop all the way to writes app code in addition to markup, CSS and javascript, in my experience a designer that doesn't have a solid understanding of raw markup, CSS and javascript is a liability.

Taken to an extreme this is similar to you saying I'd make an excellent plumber if I could drive the truck and had a couple of helpers that actually knew how to do plumbing.

You can't tell me with a straight face that a designer that doesn't have a solid grasp of the underlying principles of how front end code works isn't going to (at least occasionally) end up cranking out the worst sort of pie-in-the-sky speculative horseshit that's a rugged nightmare to mimic on the web, and every time they do they end up taking a big ass bite out of the project budget when the rest of the team is scrambling around trying to sort out the cross browser issues with the hot mess of a design comp they've just been handed.

I'll pass, thanks.

I can tell you, because it happen every day. It happens to me every day. And if you don't believe me, just read around the comments from people, here and on the article page, that do exactly that.

By the way, there are also comments of people saying that designer must think a bit over what's technically possible, to innovate. Figures. ;)

The problem however isn't in agreeing or not, but in not being so sure that your point of view is the right one.

And I'm talking with a straight face, yes. :)