Water is a good, predictable process. It's just result bad. If the result is not important, then use waterfall.
No, Waterfall is bad precisely because of the inherent unpredictability of a given project.
Never in all of history was a large software project speced out and built on time.
Software lives in a dynamic environment, so the process has to be mutable.
Maybe the answer is not 'Agile', but it's definitely 'agility'.
If we set longer term term, rounded goals, but with smaller iterations, then there's a possibility, but not a big Waterfall.
Why we should use something else, more complex, instead of Waterfall, for a single sprint? Waterfall is good enough and predictable enough for a 2-week sprint.
Yes, the result of a single waterfall will be bad, we plan for that, but accumulation of knowledge will lead us to success.