In the early days I thought forms shouldn't change. I was upset when the head of the style I was doing at the time, changed a kick because it was thought the original was too difficult for some people to do. I felt forms were sacred. At the peak of my development and training I was able to train with many senior masters and even the grandson of the founder. Each did the same form but with totally different interpretations and often blatant differences. From that I learned forms are not sacred, nor is there a single right way to do things. (there however wrong ways to do things). My conversations with the top masters who set organizational standards, allowed me to understand that without a unifying standard, the organization itself cannot exist, but that is a separate issue from the form itself and how it should or could be done. Changing a kick in a form is nothing more than a kick. Changing a kick in a form that is practiced by thousands within an organization is detrimental to the style. Adherence to the accepted standard is what makes the group.
In my experience I have only met a small handful of people who really understood the meaning behind the forms. With good kata the experience and application comes first and the solo form practice comes after. What I see most is people doing forms for the sake of doing forms. Like dance the meaning is found in the precision of the action. This is Shimejurusan kata. The purpose is self perfection through movement. with this type of performance, the application is irrelevant. This is why most people are unsure about what the actions really mean in application. Could be this , or could be that. It's all arbitrary. As if you were learning to dance the Tango and some instructors want your hand equal with your shoulder and others slightly below it.
In contrast when the form is application based what is important is getting the job done. Esthetics don't matter that much. It's a matter of repetition and having the tool handy when needed. Forms are performing the needed task of repetition and mindfulness. If the application is forgotten to history or no longer relevant why practice it? Change it to something functional. That of course holds the presupposition that you know through experience, what is and what is not functional.
Changing the form also has greater implications if the intended audience is more than just yourself. The change would need to work across time and across a multitude of different people with different body types and limitations.
My own personal philosophy is Shu, Ha, Ri.
Shu, block type print and standard performance
Ha, cursive writing with your own flavor but still recognizable.
Ri, your own personal signature developed over time and experience, no limits on movement or interpretation.
But when teaching, go back to Shu, the standard.
I didn't proof read this like I usually do. I hope it's legible.