A much better approach is to simply clean up your noisy tags. There is a section in the Creating Catalogs sticky discussing the importance of having clean, meaningful tags if you want to use the Genres section. I personally don't use tags that others have applied to books, as I find them virtually useless, and at best, inconsistently applied depending upon the source of the book. Better to do the cleanup on your entire library once, then integrate applying meaningful tags as a regular part of your workflow when adding new books.
If there's a compelling use case to having a section organized by a custom column, I'd consider adding that feature.