It's definitely something you should consider when considering your approach to an application rebuild. It has a high value for risk mitigation.
I will definitely put this in the bag of tricks for approach on rebuild projects. I can see a lot of situations where it would be valuable.
I can also see a lot of clients who won't go for it, but that doesn't mean it isn't useful.
Even ruling it out as an approach will have value to many projects. Offering it allows you to say it was there, but removed from consideration. This will help make it clear that the large, monolithic project approach (and related challenges) was explicitly selected.
In software we leverage some construction terms when we talk about software projects.
Greenfield - a new software project that is not built on a previous project. AKA - blue sky, carte blanche.
Brownfield - a project that is adding onto an existing product. AKA - enhancements, feature work, new version development.
I am going to add to this the idea of Bluefield. This is a project that is a rebuild, from the ground up, of an existing application.
This is very particular to software and I don't know if it has a counterpart in traditional construction.
This project is neither Greenfield (not brand new because it must fulfill requirements of the original system) nor Brownfield (not built on an existing product).
Why are the fields blue?
Let's say that Bluefield projects are akin to the blue sky of a new project (you often have a clean slate on technology), but you can have some sadness about the passing of a tried-and-true system that served you well for some period of time.
Blue is also associated with harmony, faithfulness, and imagination all traits that should be valued in our rebuild project -
Harmony in important features.
Faithfulness to the business intent.
Imagination required to overcome project challenges.
Rebuilding software applications is something I've thought a lot about in the last 18 months.
Rebuilds are special and have special considerations.
I wrote a blog about it for work you can read here which talks about some obvious pitfalls.
Here is another thought - what people like about their old system is actually more important than what they don't like.
This may seem obvious but here is the hard part: they are not going to tell you the things that they like. They are going to spend their time telling you what they hate about their current system.
This can happen for a number of reasons. It can happen because complaining is fun. It can happen because it is easy to criticize. And, it can happen because people do not want to be allied with the old regime once the winds of change have begun to blow.
Often, hated features are simply old and would have been corrected by updating the system.
You have to be careful and look hard for what they love, what was great, and what they have to have.
And here is the biggest catch of all. Sometimes people love features that they do not know they love because those features are so well done that they don't even realize that those features are there.
How will you know they love them? How will you be able to recreate or improve upon a feature that is so great that it is barely perceptible?