Isn’t this common sense though? How else would you re-write a complex, legacy system? But then again, I feel the same way about all virtues Martin Fowler extols.
Most of the redesigns are done in the "big redesign in the sky" fashion, that mean we rewrite a new system from scratch and when it have equivalent features as the old system we redirect traffic to it a "big bang" introduction. This usually goes wrong because it take too much time to have an equivalent system, and redirecting the traffic in one shot add to the risk of such a project. It also create frustration between the people maintaining the old system and thoses creating the new one. This said, a lot of companies still do that!!
