JD-EE
I get the impression that one of the best improvements for a pitot would be some form of airflow measurement out of the drain hole.
That is actually a very astute idea to validate a pitot tube's proper functioning.
Properly designed, that measurement could be done with a hot wire anemometer.
Basically, if there is flow, it is likely to be a valid measurement.
No flow, and the measurement is invalid.
We still have the problem of what to do when the reading is invalid on multiple sensors.