This is good advice as far as it goes, but it doesn't go far enough. For starters, it is important to remember that message, content, and actions are closely related. Put somewhat crassly in marketing terms, in the long run you can't sell a product as being a good one if it isn't a good one. Consumers will eventually figure out that your product is not as advertised. Proclaiming a gospel of love, hope, and service effectively requires a congregation to be loving, hopeful, and given to service. If, that is, a congregation preaches a message that is not overly focused on the institution of the church, it really does need to be a congregation that is not overly concerned about institutional issues and needs. The truth is a good deal of a church's messaging is not verbal and not intentional.
While Ehrich's point is well taken, furthermore, it might be better stated as a positive than as a negative. A church's message should be more about what it is rather than what it is not. If a congregation is lively, generally warm and open, and engaged in vital ministries, its messaging will reflect these qualities and in the process avoid projecting judgmental, harsh, condescending, and self-serving ones. Ehrich is correct, but it just seems wiser to focus on what the church should be rather than what it should not be.
Finally, a church's messages need to be vital as well as fresh. The single most important element in effective preaching, for example, is the ideas that it communicates. If the preacher has not invested studious reflection in her sermon, it is not likely to spark the interest of his audience. If the content is not relevant and well thought it, it will communicate these negatives no matter how much attention is given to delivery. That is to say, a church's message is not going to be fresh unless the church has invested itself in the message, given time and thought to its content. To the extent that we are communicating ideas, they have to have depth to them as well as relevance.
If "the medium is the message," the message is also the medium, which is a cute way of making an important point. The content of our messages inevitably has an impact, for good or for ill, on the manner in which we communicate them. Medium and message are in a dynamic relationship with each other. Fresh messages require an engaged and vital messenger, and such a messenger is far more like to send fresh messages.