RR_NDB:
FDR, specially in teething phase of a new airliner would "benefit" to record some information coming from important sensors? (raw data from AoA vanes, Pitotīs etc.)
Two problems: First, think about the volume of raw data that could be collected from the internals of each subsystem. The FDR architecture would have to be revised significantly. And since that is a certified part of a production aircraft, backing down to the 'standard capability' FDR would require recertification.
Second: The internal charger/battery data is taken from the same sensors that drive the charge controllers. So if these are faulty, so too is the recorded data. Faulty data might tell investigators something. An anomalous zero cell voltage reading may indicate a broken sense lead for example. But at what point do we stop incorporating redundant sensors into systems just to satisfy these enhanced FDR requirements?
This is what certification test instrumentation is for. Redundant and separate from the systems under test. There just isn't much room left on an aircraft instrumented to this degree for SLF.