Mats Einarsen highlights the importance of any successful design having data at its core:
A “great” design which produces bad outcomes — low engagement, little utility, few downloads, indifference on the part of the target market — should be regarded as a failure.
On the flip-side, a design that doesn’t in some way take a risk or align to a value not determined by data (e.g. a brand value) should also be tried. Luckily, most of these things can be A-B tested.