I think I see it differently as we have just spent 3 years developing a CMS at our company and every decision has been a well thought out and concious one. We spent 3 weeks planning when we first conceived the plan.

We have only had to do 2 refactors in that time on 2 controls. That was more about understanding our customers needs more as we progressed rather than not enough planning though.

Previous to that I built a custom ecommerce site for a wholesale distributor. That whole process was more suited to a quick hack over a well thought out decision. That's why I say I agree in principle, so long as the project allows it.