Based on my Dreamforce 2012 Session, Force.com to Heroku and Back: Sharing Dynamic Logic I wrote an article on developerforce which explains how to balance flexibility and implementation time by leveraging Heroku from Force.com. Here is the opening paragraph:
In today’s rapidly changing marketplace, businesses are experimenting more than ever, so that they can innovate and produce competitive advantages. As software designers and developers, our challenge is to design solutions that attempt to balance between what appears to be conflicting goals: flexibility and the overall implementation time. Writing a system that is too flexible is extremely difficult to design, implement and ultimately test. Depending on how complex of a solution it may take longer or cost more than sponsors are willing to pay. This article provides one solution that elegantly balances flexibility and implementation time by leveraging Heroku from the Force.com platform.
You can read the full article here.