For “It’s easier, and better web design practice to get something online quickly, and tweak, or manage your design as it grows.” This, for me, is just lack of experience: ignorance of the interdependencies between elements (purpose, use, visual design, interaction design, IA/content organization, etc. etc.). Best web design practice is to plan what you build, so to design for expansion. Otherwise a wild weed grows organically and loses the sense clarity and organization necessary for trust, which is indispensable to good communication. This for the same reason you build nothing else this way: not a house, shed, or even bird house. Plan, design, produce, evaluate. Rinse and repeat.