With the benefit of hindsight, I think UML had quite possibly reached not only its actual, but also its potential, peak in 2000: as a medium for software sketching, people only ever needed the basics from it. However, the standardisation community developed an ambitious vision for UML that far exceeded sketching. Whether or not that vision could ever be realised can be seen as a matter of genuine debate: what seems unarguable to me is that such a vision was deeply unsuited to any standardisation process.