Cabin crew should certainly be encouraged to have flying skills, and be able to use the radio. Just as partners of pilots in light aircraft are encouraged to undergo a basic survival course in how to use the radio, call for help, and land it if the PIC snuffs it enroute.
Having gone through the scenario on a BA111 simulator at Cranebank, with 30 hours PPL, I did push the wrong button initially (disconecting the autopilot) but on being allowed a second chance, was talked down successfully at LHR....
So if pilots are incapacitated, and it does happen, perhaps even the most basic training would be better than nothing.