Is Ground in a circuit nothing more than a return path?
Ground, or more specifically "ground potential" is simply a reference node within your circuit. 

Voltages are not absolute things, but rather a difference in potential between two nodes in a circuit. In other words a voltage is always measured as the difference between two points in a circuit.

To make circuit analysis easier we tend to use a single node in the circuit (usually the point of lowest potential, but not always) and measure all voltages relative to this zero point as it makes calculation easier. This 0V point is what we call ground.

Current will flow through ground (assuming there is a complete path), but it's not necessarily the "return path" - current can flow into ground, yes, but it can also flow out. It is simply the point in the circuit that we call 0V.




  Since a battery separates electrons and protons to opposite ends 


Batteries don't really collect protons at one end and electrons at the other, although you are right that there is a build up of electrons at one end.

A battery uses redox chemical reactions which oxidise the anode (anode material loses electons) and reduce the cathode (cathode material gains electrons). The process generates a voltage because as you say you have an excess of electrons at one end and a deficiency of electrons at the other.

When you connect a circuit between the anode and cathode, the excess of free electrons at the anode flow through your circuit to the cathode (remember, cathodes are pussitive =^_^= ) to equalise the charge. This is why a chemical battery runs down - the reaction runs out of material to redox.


  And since short circuits involve an unintended path to ground


Not necessarily. A short circuit is simply an unintended current path between two nodes in a circuit. One of the nodes could be ground, but it doesn't have to be. 

For example you could short out the 5V and 12V rails on a computer PSU. This wouldn't entail a short to ground, but it would still be damaging none-the-less. In this example the electrons flowing through this short don't want to go to ground per say, they simply want to find a route to a point of lower potential and flowing from 12V to 5V will do just that.

Of course in the end current only flows in circular paths, so in the end the electrons that enter a circuit will always be equal to the electrons leaving the circuit.