We have a similar method under the hood, except it's purely text-based search-and-replace. The model decides what to replace. It seems to be consistent and is easy to implement.
Gut feeling doesn't account for much though - I'm working on an evals system to be able to quantify system performance. It won't be cheap to run.
It could easily be that your method is superior.
I'm also curious, how are you guys evaluating the performance of your models?