As a professional Computer Systems Engineer, I have seen the effect of 'feature creep' in many and varied manifestations. Basically, this occurs when the user really needs one or two critical capabilities, but ends up with a system with hundreds or thousands of other 'nice-to-haves', often at the expense of those few items they really wanted (and at a cost far in excess of what they could afford). Moreover, this plethora of features usually results in a fragile, bloated product which, as discussed earlier, is difficult or impossible to maintain.
When interviewing software clients, I usually request a Statement of Purpose (SOP), a simple, concise sentence or two describing what they want.
In the case of my amplifiers, I base all of my designs on my own SOP:
"I want an amp that sounds great, unique, is easy to understand and use, and allows me to switch between a round, responsive, dimensional clean sound, and the natural sound of the same circuit when overdriven, both independent of overall volume."