How does one calculate the voltage ratio V+/Vo for this circuit?
Okay, if you assume no load at all (infinite impedance on V+), the series capacitor gives you an arbitrary offset voltage corresponding to the initial condition of the capacitor. Since there is no load, the capacitor voltage will remain the same forever. Other than that arbitrary voltage you can ignore the capacitor. 

If you assume some resistive load, then I think you can calculate it similarly to the first example.