The problem with Excel spreadsheets is that the overwhelming majority of users are not programmers or engineers, they are clerical workers with no real understanding of what they are doing. Knowledge, such as it is, is passed on in a monkey see, monkey do, fashion, producing imitation without insight.
This proposed tool is for engineers, not clerks. You download it and use it locally right? Because if it requires the spreadsheet to be uploaded then that is another technical hurdle and one which breaches most people's security requirements.
Excel already does most of this, the problem is that people can't comprehend what it is telling them, your tool is no different.
Almost all Excel users are not programmers, you're definitely right. If by clerical workers you mean people who are just entering data into the sheet or reading an output then, yes, they don't need to understand what the sheet is doing.
However there are loads of people who build there own sheets: analysts, consultants, managers, marketing, accountants and yes engineers. These are the people who spend the most time using excel. Excel let's you build a very complex model formula by formula. It's often a model more complex than you might be able to map out initially. Whilst they are not programmers they are still smart enough to understand the sheets they've built. The issue is Excel right now is so opaque about what its doing and where the numbers come from. It makes this task much harder than it needs to be.
This proposed tool is for engineers, not clerks. You download it and use it locally right? Because if it requires the spreadsheet to be uploaded then that is another technical hurdle and one which breaches most people's security requirements.
Excel already does most of this, the problem is that people can't comprehend what it is telling them, your tool is no different.