The only caveat to the final point - and any time one person is given decision making power over something, is to give the community a chance to voice their desires and preferences up front. Not necessarily feedback, but a compilation of preferences that a designer can use to make sure they are creating something that accurately reflects the needs and desires of the community as a whole, not just their own personal preferences, or guesses at what everyone else wants. This way democracy can still be involved without the negative side effects you describe above.
The only caveat to the final point - and any time one person is given decision making power over something, is to give the community a chance to voice their desires and preferences up front. Not necessarily feedback, but a compilation of preferences that a designer can use to make sure they are creating something that accurately reflects the needs and desires of the community as a whole, not just their own personal preferences, or guesses at what everyone else wants. This way democracy can still be involved without the negative side effects you describe above.