We did quite well back in the day with the "UML as blueprints" approach, and I personally felt that for new complex systems that mapping between various diagram

We did quite well back in the day with the "UML as blueprints" approach, and I personally felt that for new complex systems that mapping between various diagrams and the use cases helped greatly in clarifying a larger OO system before we started writing code. I felt creating diagrams and getting consensus at the start of iterations made us significantly more productive and produced better results. But most active tooling and education for UML was always CASE-oriented, which was way too heavyweight for such a small org. I would use more "UML for sketch" tooling - like OmniGraffle with good (internal) stencils - which allowed for iterative improvement to the diagrams. I actually switched from Linux to Mac for OmniGraffle. Invariably the UML tooling of the day was too cumbersome, because it was geared toward making more formal models from the outset. It is the UML sketching which I have kept throughout my career, and lamented that as CASE died, there hasn't been anything else to supply baseline education nor has there been any evolution (or simplification, or unification.) I suspect creating such things just isn't that attractive without the CASE money being there.