It was a popular explanation for the breaking apart of Yugoslavia and now it is often used to explain the threatening break-down of Iraq and Syria: those states are artificial.
However, all states are artificial. If the borders aren't the product of some foreign dictate they are the limits of what some king long ago managed to conquer and hold. If you look long enough you will always find fissure lines along which a country could break apart. There are always regions that feel neglected, there are always rich regions that don't want to pay for poorer regions elsewhere and there are always regions that there local traditions are something special.
The "artificial state" myth assumes that countries come into existence from the bottom up. As a consequence its supporters assume that if you take the present central government away and empower regional forces they will recreate the central government. But it doesn't work that way. Once you empower regional forces they will want to keep that power and resist the central power.
If you wanted to keep Yugoslavia together you had to deal with Milosevic because he held the power. If you wanted to keep Iraq together you should have kept after the fall of Saddam the existing structures. If you want to keep Syria together you have to deal with Assad. Empowering local factions, even when they constitute the majority like the Shiites in Iraq and the Sunni in Syria, destroys the heart of the state.