Let customers drive your product road-map – let them not dictate it. I have witnessed both sides of this divide. A strong product management team invariably has strong, unambiguous and pragmatic product road-maps. When these are taken and presented to customers and prospects they understand. They feel reassured that there are smart minds taking care of the future of products they have bought or are contemplating to buy. They accept your argument even if they are not entirely happy with it.
Then they are iffy product road-maps. These are nebulously defined, self contradictory and are either terribly grandiose or pathetically unimaginative and can be seen through immediately. Customers sense the despondence and move in to become surrogate product managers. All hell breaks lose and the product road map is first hijacked and later bombed away by a combination of lack of consensus, impracticality of implementation and rudderless thought leadership.
It is a misconception that product road-maps will automatically emerge if they are left to customers entirely. Customers want to get along with their jobs as they expect the product manager to get along with his.
Post Script: I recently came across a product road-map presentation that had this disclaimer – “brave propositions have been made in this document”. Brave? Or did the author mean Foolhardy?