I have had a similar issue with a UX/design person. I think the main problem though is process. The design person should be challenged and accept criticism, and

I have had a similar issue with a UX/design person. I think the main problem though is process. The design person should be challenged and accept criticism, and revisit their designs. Engineers can also fall into similar traps of following trends and over-engineering things (smart people like to make complex things without even realizing it). Without the structure in place to correct these oversteps, designers can have similar problems.