Why did Yanagi have to go?

[Sava]

Because 2 bases are better than one.
Of course, splitting outcast and corsair docking locations in Sigma-13 will increase the number of their interactions.

Also, it's a known fact that a base in certain system attracts players of the associated NPC faction.
Just take a look at OC activity in Newcastle, Lorraine and Eta.
Or sairs in Lambda etc.
Suuuure.