Some designers are mind-blowing at visuals but not as experienced in interaction design. Some designers are brilliant product strategists but their design execution is weaker. There are incredibly difficult problems in each area of design, and having the right designers working on the problems that are well-suited to their skills is critical. You cannot swap one designer for another and expect to get the same outcome on a project. Generally, you’ll need all of the above for a strong design. If you can only have one designer on your team, it’s better that that person is a generalist rather than exceptionally good at any one area but weak in the others. If you have a team of designers, then having more specialized designers may work.Julie Zhuo.