The following is a quote from Sebastian Haffner's Preußen ohne Legende, translated by me. I found it a very interesting analysis, but I'm curious what the historians here think of its validity.
In its birth and its rise to greatness, Prussia is most definitely a child of the European era between the Peace of Westphalia and the French Revolution. In no other age could a state like Prussia have come up in the world like it did. This era could be called the age of puberty of European power politics, a time of wild impulses and daring antics. During this time, the balance of power in Europe changed more kaleidoscopically than ever before or since.
Before (also for a century and a half, and strangely similar to the present situation*) there had been only two real powers in Europe, in whose endless conflict – open or dormant – all others had to find their place: Habsburg and Bourbon. Afterwards, from the end of the Napoleonic crisis to the First World War, Europe lived in a stable, carefully balanced five-power system. But between 1648 and 1789, things in Europe went like in a gambling hall. For 140 years, the continent looked like a stock exchange of power, where prices constantly rose and fell.
* The book came out in 1979; 'the present situation' refers to the Cold War between the US and the USSR.
Well, considering the fact that 1789 was followed by 25 years of bloodbath on the European Continent followed by the spread of revolutionary ideals that would destroy a millenium of feudal laws and traditions triggering the rise of german and italian nationalism from the 1840s to the 1870s soon followed by panslavism and nationalism in previously repressed populations (Poland, Romania, the Balkans, etc..) which in turn would directly lead to the two world wars that engulfed the continent in the XXth century I don't really think that the period you designated can be defined as "followed by a period of relative stability"
edit : as far as the "before" period is concerned we have the thrity years war, a war that ravaged the whole continent with roaming mercenary bands pillaging the countryside because their employers couldn't pay them anymore.
And before this war we have the French Wars of religions, France being the most powerful country on the continent having it fall into civil war was not the most stabilizing factor.
The more I think about it the more I feel like the peaceful and stable period is indeed 1648-1789, the wars of religions are mostly over, France stabilizes and consollidate its dominance on the continent, Prussia Austria and Russia stabilize their frontier by dividing Poland, the Ottoman threat is definitly stopped, the exploration and colonization of the Americas bring economic growth and stability...
Just a note we just had a podcast about this! :)