The "best" design should be an optimum compromise between many factors and constraints.
The compromises have to take into account to reach a sensible and acceptable design.
An excellent designer must be aware of the systematic organization and settles disputes between different displines in the overall design.
An optimum design may not have the best perofrmance in all displines, but it must be the best integration. Actually, the multi-displine optimization nethod are now often used in our work.