Below you will find a presentation I prepared over a year ago for a customer who was contemplating replacing their entire software back bone, moving from one legacy full stack to another. The reasons for their contemplating this are ultimately not material to the discussion, except in that it provided the catalyst for my own thought processes. I could see momentum behind the "do something" mantra was building and sought to help them avoid rushing off the cliff in a way that would result in huge disruptions.
My slide deck was intended as an introduction to both the MVC design pattern and software abstraction as a concept, presenting it at a time when they would most benefit from adopting the sort of approach it represented. Ultimately they took a similar path to the one I outlined, but with a critical difference in that they moved to more SASS systems rather than build their own.
If you have questions, please feel free to ask me. I've helped large companies do this sort of transition on many platforms - the tools themselves are not as important as the way they are employed.
The Case for Retooling and Abstraction
Feel free to share this if it makes the conversation with your management or stakeholders easier. I only ask that you share it from the source link so that I have some idea as to how widely it is used.