While the ballast resistor can go bad... you would know in an instant if it did.
After the engine starts, all the coil power flows through the ballast resistor. The failure mode for a ballast resistor would be to "burn open". If that happens, the resistive element burns in half and no more electricity would flow. In short... no power would reach the coil and your engine would stop.
As above, normal resistance would be between 1 to 2 Ohms.