The funny thing about Mandel's K-7 blueprints is his crew roster. It's all Starfleet officers, no indication of civilian workers or enlisted personnel. That struck me as a throwback to the Franz Joseph works of the time.
The hangar area seems way too small for a thriving station, with very little room for embarked craft like scoutships or shuttlecraft, and none left over for travel pods, work bees and the like.
It is neat, though, how Mandel designed the innards of the station like a Federation starship. Has anyone ever done any artwork showing a starship physically docked at one of these kinds of stations?
I have to say one more thing, looking over Mandel's exterior drawings: as expected, this station design is pure TOS. It is obviously familiar with the Enterprise's design theory; exactly a space station analogue to a TOS Federation starship.
I think it would be neat to see a sister-design to this, with another tier of three outer arms and pods on a separate level, situated at angles opposite the K-class trio; kinda like the Cylon basestars in Ron Moore's GALACTICA remake.
I really like the modular concepts in this design.