You make it sounds like if Autocad had involved a designer in the process, they would have wound up with google sketch. Sometimes things need to have features, even features that 90% of users won't need 90% of the time. A good designer shouldn't be the person who decides to cut features, he should be the person who figures out how to keep the features, but in a manner that allows new users to start with a minimum of pain, and expert users to keep growing into the product. That's hard work, and it takes a lot of cleverness and creativity, but I think anybody willing to do that work would be welcome in any sane open source project.

EDIT: on re-reading my post, it looks like I'm saying Autocad didn't have designers, which is completely the opposite of how I feel. What I was trying to get it is that (IMO) Autocad is an amazingly approachable product with tons of features, just presented in a way that isn't terribly daunting to a new user.