I've dealt with many people who say they're 'technical' and 'work with programmers' only to have them say, "Hmm.. let's change this module to this side, and then add this functionality." not knowing those small changes will cost several days of work: static changes, backend peeps changing the api, circling through people trying to get things done. It can be a real issue. The best designers I've ever worked with would dive into the code with me and ask questions. On one particular iOS project, a designer would actually make custom views after showing him the basics.. it really helped me, and I can tell he learned a ton about approaching developers/ making sure a design is truly done before implementation.

In other words, I totally agree with you, but it's up to a programmer to decide if the designer fits, not the other way around.