[https://www.nola.com/business/2019/03/at-tense-meeting-with-boeing-pilots-angry-about-company-not-disclosing-737s-software.html](https://www.nola.com/business/2019/03/at-tense-meeting-with-boeing-pilots-angry-about-company-not-disclosing-737s-software.html)

  
There are numerous sources that say that pilots weren't notified about the existence of MCAS, this source is just the first of many found.  When the plane is pitching down uncontrollably, you may not be able to notice the sensor reading being off especially since Boeing didn't make a sensor mismatch notification a standard thing on the plane.

You said "I don't know enough about how pilots were trained..."  Well, they weren't trained at all nor even made aware of the new system by Boeing, which seemed to consider it a software change similar to 5.4.8.8.89 -&gt; 5.4.8.8.90 (you get the idea).  The pilots had no idea the new system was there through no fault of their own nor their airlines.

Also, I'd be careful with saying "a number of American pilots" unless you are referring to the airline.

The fact that six months in, no changes have been made isn't significant.  They might just be thorough in their review and possibly looking at other issues (see "possibly").  There is no safety reason to hurry since the planes are grounded.