Lay out, a matter of taste?

My clients ask is the lay-out of a publication a matter taste or are there criteria? Lay out should support our objectives. You should brief the designer that in this case the document is meant to guide civil servants to decide about project funding and to help local stakeholders to select and prepare project proposals. Look and feel of the lay out should support this. It should be easy to read and easy to find information. It should give an impression of reliability, credibility and be business-like. E.g. large fond and texts in two columns help readability. The choice of the illustrations can help finding information and support credibility. A design without much ornamentation makes a document more business-like.