The best designers I have worked with have been able to write textual documentation about what they want to achieve, doodle in whatever medium they prefer until

The best designers I have worked with have been able to write textual documentation about what they want to achieve, doodle in whatever medium they prefer until they have visual concepts, and then work with me to turn those concepts into functionality. Delivering PSDs is worse than useless, and the results of a skilled UX/IX designer working directly on the implementation are always better than either of us would have come up with alone.