It's an interesting project but to be honest, Regular expressions are kind of terrible as a piece of software if one is looking to embed them in larger software, especially if the regex gets at all large.
Have you can considered generating something like a formal grammar, a recursive-descent parser or a software library?
Despite this work being neat, that's still the best way to do it that I'm aware of. First reason is that English is imprecise enough that CompSci invented formal specifications to solve the problems that created. This is an immediate step back from precise requirements. Second, there's a ton tooling to automatically generate parsers from precise grammars. The languages, even BNF, are pretty easy to teach people. There's also text languages & spec methods that can make comprehensible stuff that regex's or BNF might muddy up. All of these take almost no CPU effort to deterministically produce a result from.
So, the old ways are still better for this domain if it's a production system whose cost or results matter. These methods might be useful for search/query by casual users, though. Or people that come from a foreign language likely to express queries in a weird way.
Have you can considered generating something like a formal grammar, a recursive-descent parser or a software library?