I doubt it was Dir before(unless you count Isaaq as Dir). The Daroods in those areas built them, they were the sultans there. I don't know about Tumaal/Gabooye, what's their qabiil? I doubt they are, and your theory has too many holes. The Saab are in southern Somalia, the most fertile area. Not to put them down, but with that they should be building empires. They didn't though. Very unlikely that they were in the North.Actually the majority of Northern Somalia was probably Dir before. Why are there large ancient towns? Who built them? Where did Tumaal/Gabooye come from? Perhaps they were the survivors of the settled people and were enslaved? Nomads always look down upon settled people, hard workers and farmers.