No, this isn't a "Terran is OP" QQ thread. I play Terran, so they're obviously UP and
rock is IMBA. This is about discussing the rationale behind Terrans having so many flexible extraneous structures that simply give them versatility -- versatility that other races simply don't have. Let's go through the list of "atypical" structures for all races and what makes them atypical.
TERRAN
Command Center -- allows worker units to load and unload to keep them safe, or for transport.
Planetary Fortress -- an upgrade to an existing structure that turns it into a high powered stationary defense.
Supply Depot -- can be lowered to allow units to pass.
Bunker -- repairable, salvageable stationary defense that can hold infantry units.
Sensor Tower -- gives Terrans 'sight' in a wide range.