That's called Balkanization for a reason. And it doesn't turn out well.
That is the outcome of nationalism
In contrast, Iraq and Pakistan have artificially created borders
in the case of Iraq, the British at the end of WWI got 3 distinct Ottoman provinces and combined the northern oil-rich province that was occupied by Kurdish people(a distinct Indo-European, Irani people) and the southernmost province populated by Marsh Arabs (Semitic people, mostly Shia) and they had to include the middle Sunni Arab province to join the two
The Kurds are ethnically distinct and have a homeland that is stretched across Turkey, Iraq and Iran.
in the case of Pakistan, the line dividing the Pathans into Afghanistan and the NWFP was artificially created as an outcome of the Anglo-Afghan wars.
The people on both sides are nearly completely Pathani
This is not Balkanisation, but rather reuniting populations that were artificially divided