[karurosu]

I work on a project with a decent ratio of engineers:designers. A good designer is not just "ideas people", they are fairly technical without getting into the nitty gritty.

If one side gets too much power then it can land in situations like you describe (design makes unrealistic requests, or engineering over constraints the product). When the balance is right then working becomes quite amazing, nothing better than seeing my work (engineering) used to make stuff I couldn't even think of and I can see the appreciation of helping design make their vision come true.