make the tech lab and reactor fly so production doesn’t stop when switching them.
If they can fly then it is fewer clicks to switch them from building to building (reactor up then reactor down whereas now it is building up x2 and building down x2 like when switching a barracks with reactor to a factory)
the 90 degree angle/L shape means units can get stuck if that spot is walled in, whereas square buildings do not have this issue. This is particularly troublesome for terran because the bases are essentially smaller for them because their building take up more space and must be arranged to prevent units getting stuck.
The tech lab/reactor can also prevent large units from spawning (thor tank) if the factory is blocked on the top/bot and left side.