[mimixco]

"Software product overhaul" is a terrifying term because there really is no such thing. The program you have already might be able to be modified to have a different user interface (which is what I think you might be asking for), or it might be entirely replaced by something new.

Unless you have lots of time and money to throw at this, most architect-level programmers will vote for the first solution, change the UI to make the user happy. Not a being a programmer yourself, its impossible for you to know if it's really "built on sand." It might be great under the hood and have a terrible interface; that's very common.

A real architect would need to weigh-in on the technical deficits that would be incurred by rewriting or discarding parts of the existing system, including thinking about all the switching costs of getting everyone over to the new product. Its possible that your dev team might vote for that, but more likely that they will put your feature requests in the "feature request bucket" and get to them as time and tech allow.