I really, really, really, really, very really dislike hearing one size fits all statements like this in personal finance. Sometimes a 20 year has significant savings (the rate I see with my parent company right now is a difference of .375%) over a 30 but going to a 15 just doesn't make sense for flexibility etc. On $200K you are talking about $24K difference in cost over the life of each loan in amortization and rate difference. If you pay on the same amortization schedule but the difference in rate, you are giving up about $7K in cost. Why? Sure, a 15 year may make more sense with even more savings but it does not always make sense for every customer.
I don't do loans anymore but when I did I always, always, always, always- listened to the customer, figured out their specific situation, wants and needs and then tailored a solution that best addressed them while educating them on their options along the way.