I think you're both right.

I have also met a lot of completely unreasonable designers that would insist on the most minimal things (even to the detriment of usability), and would act like assholes towards developers.

I have also had situations where developers would beg to work with a certain designer because their experience made development a breeze, even for complex layouts. Funny enough, the projects where this designer worked would always get done, and the visual result was always great.