No specification for time resolution or e.g. complexity of the connected cable system has been said yet.
In practice, a lab standard fast pulser (e.g. 1 ns rise time) would be sufficient for many tests. I remember a TDR instrument dedicated for fault localization in TV antenna distribution systems, that been manufactured in Germany in the 70th. Of course, the voltage had to be suffcient low not to damage connected TV receivers, so it had to be restricted to a low voltage step. But it gave a visual representation of a network with multiple regular discontinuities and a failure. I agree, that you won't be able to localize multiple faults in some cases, but I don't think, that this is a common problem.
A manufacturer offering specialized TDR systems, will want to set apart from competition and start to offer advanced features. But that doesn't mean, that you can't work with a basic instrument.
100 ps pulses would "melt" after a few 10 meters due to cable dispersion.