Most of the measures to check oil quality so far amount to a slightly higher tech version of scraping the oil off the magnetic plug and rubbing it between a finger and thumb and cutting open the oil filter to check for bits of debris.
Newer methods of real time, in flight, monitoring need to be developed. Doubtless this will lead to more alarms and precautionary landings, but it is better than the alternative.
The idea of irradiating components and then monitoring filters and plugs for the build up of radioactive particles due to wear has some merit, but I'm not sure environmentalists or even passengers and crew would be entirely happy.