It's time to become model-agnostic.
I'm a big believer in the value of theoretical rigor - I guess that comes from my graduate work. In fact, I tend to think that anyone who works in a professional services field should have a solid grounding in the theories that underpin their specialty. Change management, in particular, is a field that can so often get mistaken for a touchy-feely offshoot of HR, I'd like to see more practitioners with advanced degrees in the field.
(An example of a diagram which looks nice, but means almost nothing when you think about it.)
However - and it's a big 'however - it's important to remember that if all the change management models we learn in degree programs were as true as 2+2=4, we wouldn't call them 'theories'. We'd call them 'universal truths'.
And therein we have the basis of one of the biggest problems in change management: The $25,000 diagram.
What do I mean?
All too often I see change management professionals who try to use the theory approach to solve every change-related challenge. They dust off their favorite change management model from a textbook, plug in some numbers and arrows, add some bullet points about the marvelous results this model will magically achieve - and voila! The client gets a nice-looking PowerPoint presentation, the heart of which is an attractive diagram that appears to demonstrate a few simple actions that will transform the organization. And a bill for $25,000 for this insight.
There's a big difference between theory and implementation
Theory is great as far as it goes, but it's only part of the solution - in my experience, implementation, execution and results are more than 75% of the change process.
What's more, every organization is different, and so far I've never encountered one that fit neatly into a single change model or approach. There's always an angle that isn't accounted for in the theory, a business function which isn't accommodated in the handy 4-square diagram, and a learning curve which isn't reflected in the results grid.
So my recommendation, when you're planning your change process, is to take a model-agnostic approach. Instead of relying on a particular theory, look for a plan which spends more time on how the implementation will roll out - and how it will affect your people - than on how it should roll out, based on the theoretical diagram.