This reminds me of another interesting point I recently saw raised regarding WWII. WWII is often credited with ending the Great Depression, but in reality was primarily helpful insofar as it made it politically viable for the US government to inject a massive stimulus into the economy far eclipsing the New Deal (and other governments to do likewise).
Tying that to the broken window fallacy, it seems the ultimate conclusion is that wartime economic policy without the actual war would have been a better way to achieve the desired result.
Of course the reality may not be so simple from a US perspective when we consider that all the broken windows were outside our borders, the national focus and urgency imposed by the war, and that removing the war from history would have dramatic unpredictable effects on our world today. Nevertheless, the idea seems convincing enough to me in abstract that starting a new war purely for perceived economic benefits would be an inefficient alternative to simple progressive economic policy on an equivalent scale.